diff --git a/app/components/govuk_component/accordion.html.erb b/app/components/govuk_component/accordion.html.erb
index fc48e74c..6a04ed8c 100644
--- a/app/components/govuk_component/accordion.html.erb
+++ b/app/components/govuk_component/accordion.html.erb
@@ -3,7 +3,7 @@
     <%= tag.div(id: section.id(suffix: 'section'), class: section.classes, **section.html_attributes) do %>
       <div class="govuk-accordion__section-header">
         <h2 class="govuk-accordion__section-heading">
-          <%= tag.span(section.title, id: section.id, class: "govuk-accordion__section-button") %>
+          <%= tag.span(section.title, id: section.id, class: "govuk-accordion__section-button", aria: { expanded: section.expanded? }) %>
         </h2>
         <% if section.summary.present? %>
           <%= tag.div(section.summary, id: section.id(suffix: 'summary'), class: %w(govuk-accordion__section-summary govuk-body)) %>
diff --git a/app/components/govuk_component/accordion.rb b/app/components/govuk_component/accordion.rb
index 6c056a85..f89113c4 100644
--- a/app/components/govuk_component/accordion.rb
+++ b/app/components/govuk_component/accordion.rb
@@ -19,19 +19,26 @@ def default_classes
   end
 
   class Section < GovukComponent::Slot
-    attr_accessor :title, :summary
+    attr_accessor :title, :summary, :expanded
 
-    def initialize(title:, summary: nil, classes: [], html_attributes: {})
+    alias_method :expanded?, :expanded
+
+    def initialize(title:, summary: nil, expanded: false, classes: [], html_attributes: {})
       super(classes: classes, html_attributes: html_attributes)
 
       self.title   = title
       self.summary = summary
+      self.expanded = expanded
     end
 
     def id(suffix: nil)
       [title.parameterize, suffix].compact.join('-')
     end
 
+    def classes
+      super + (expanded? ? %w(govuk-accordion__section--expanded) : [])
+    end
+
   private
 
     def default_classes
diff --git a/docs/index.html b/docs/index.html
index 58a1d114..474979b3 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -914,98 +914,6 @@
   border-bottom: 1px solid #b1b4b6;
 }
 
-/* line 12, node_modules/govuk-frontend/govuk/objects/_button-group.scss */
-.govuk-button-group {
-  margin-bottom: 5px;
-  display: -webkit-box;
-  display: -ms-flexbox;
-  display: flex;
-  -webkit-box-orient: vertical;
-  -webkit-box-direction: normal;
-  -ms-flex-direction: column;
-  flex-direction: column;
-  -webkit-box-align: center;
-  -ms-flex-align: center;
-  align-items: center;
-}
-
-@media (min-width: 40.0625em) {
-  /* line 12, node_modules/govuk-frontend/govuk/objects/_button-group.scss */
-  .govuk-button-group {
-    margin-bottom: 15px;
-  }
-}
-
-/* line 48, node_modules/govuk-frontend/govuk/objects/_button-group.scss */
-.govuk-button-group .govuk-link {
-  font-family: "GDS Transport", arial, sans-serif;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-  font-weight: 400;
-  font-size: 16px;
-  font-size: 1rem;
-  line-height: 1.1875;
-  display: inline-block;
-  max-width: 100%;
-  margin-top: 5px;
-  margin-bottom: 20px;
-  text-align: center;
-}
-
-@media print {
-  /* line 48, node_modules/govuk-frontend/govuk/objects/_button-group.scss */
-  .govuk-button-group .govuk-link {
-    font-family: sans-serif;
-  }
-}
-
-@media (min-width: 40.0625em) {
-  /* line 48, node_modules/govuk-frontend/govuk/objects/_button-group.scss */
-  .govuk-button-group .govuk-link {
-    font-size: 19px;
-    font-size: 1.1875rem;
-    line-height: 1;
-  }
-}
-
-@media print {
-  /* line 48, node_modules/govuk-frontend/govuk/objects/_button-group.scss */
-  .govuk-button-group .govuk-link {
-    font-size: 14pt;
-    line-height: 19px;
-  }
-}
-
-/* line 61, node_modules/govuk-frontend/govuk/objects/_button-group.scss */
-.govuk-button-group .govuk-button {
-  margin-bottom: 17px;
-}
-
-@media (min-width: 40.0625em) {
-  /* line 12, node_modules/govuk-frontend/govuk/objects/_button-group.scss */
-  .govuk-button-group {
-    margin-right: -15px;
-    -webkit-box-orient: horizontal;
-    -webkit-box-direction: normal;
-    -ms-flex-direction: row;
-    flex-direction: row;
-    -ms-flex-wrap: wrap;
-    flex-wrap: wrap;
-    -webkit-box-align: baseline;
-    -ms-flex-align: baseline;
-    align-items: baseline;
-  }
-  /* line 84, node_modules/govuk-frontend/govuk/objects/_button-group.scss */
-  .govuk-button-group .govuk-button,
-.govuk-button-group .govuk-link {
-    margin-right: 15px;
-  }
-  /* line 89, node_modules/govuk-frontend/govuk/objects/_button-group.scss */
-  .govuk-button-group .govuk-link {
-    text-align: left;
-  }
-}
-
 /* line 4, node_modules/govuk-frontend/govuk/objects/_form-group.scss */
 .govuk-form-group {
   margin-bottom: 20px;
@@ -1943,8 +1851,6 @@
   position: relative;
   width: 100%;
   margin-top: 0;
-  margin-right: 0;
-  margin-left: 0;
   margin-bottom: 22px;
   padding: 8px 10px 7px;
   border: 2px solid transparent;
@@ -1996,36 +1902,36 @@
   }
 }
 
-/* line 55, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 53, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button:link, .govuk-button:visited, .govuk-button:active, .govuk-button:hover {
   color: #ffffff;
   text-decoration: none;
 }
 
-/* line 64, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 62, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button::-moz-focus-inner {
   padding: 0;
   border: 0;
 }
 
-/* line 69, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 67, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button:hover {
   background-color: #005a30;
 }
 
-/* line 73, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 71, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button:active {
   top: 2px;
 }
 
-/* line 82, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 80, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button:focus {
   border-color: #ffdd00;
   outline: 3px solid transparent;
   box-shadow: inset 0 0 0 1px #ffdd00;
 }
 
-/* line 110, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 108, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button:focus:not(:active):not(:hover) {
   border-color: #ffdd00;
   color: #0b0c0c;
@@ -2033,7 +1939,7 @@
   box-shadow: 0 2px 0 #0b0c0c;
 }
 
-/* line 122, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 120, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button:before {
   content: "";
   display: block;
@@ -2045,19 +1951,19 @@
   background: transparent;
 }
 
-/* line 146, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 144, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button:active:before {
   top: -4px;
 }
 
-/* line 151, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 149, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--disabled,
 .govuk-button[disabled="disabled"],
 .govuk-button[disabled] {
   opacity: 0.5;
 }
 
-/* line 156, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 154, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--disabled:hover,
 .govuk-button[disabled="disabled"]:hover,
 .govuk-button[disabled]:hover {
@@ -2065,14 +1971,14 @@
   cursor: default;
 }
 
-/* line 161, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 159, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--disabled:focus,
 .govuk-button[disabled="disabled"]:focus,
 .govuk-button[disabled]:focus {
   outline: none;
 }
 
-/* line 165, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 163, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--disabled:active,
 .govuk-button[disabled="disabled"]:active,
 .govuk-button[disabled]:active {
@@ -2080,49 +1986,49 @@
   box-shadow: 0 2px 0 #002d18;
 }
 
-/* line 174, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 172, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--secondary {
   background-color: #f3f2f1;
   box-shadow: 0 2px 0 #929191;
 }
 
-/* line 178, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 176, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--secondary, .govuk-button--secondary:link, .govuk-button--secondary:visited, .govuk-button--secondary:active, .govuk-button--secondary:hover {
   color: #0b0c0c;
 }
 
-/* line 197, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 195, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--secondary:hover {
   background-color: #dbdad9;
 }
 
-/* line 200, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 198, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--secondary[disabled]:hover {
   background-color: #f3f2f1;
 }
 
-/* line 206, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 204, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--warning {
   background-color: #d4351c;
   box-shadow: 0 2px 0 #55150b;
 }
 
-/* line 210, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 208, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--warning, .govuk-button--warning:link, .govuk-button--warning:visited, .govuk-button--warning:active, .govuk-button--warning:hover {
   color: #ffffff;
 }
 
-/* line 229, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 227, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--warning:hover {
   background-color: #aa2a16;
 }
 
-/* line 232, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 230, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--warning[disabled]:hover {
   background-color: #d4351c;
 }
 
-/* line 238, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 236, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button--start {
   font-weight: 700;
   font-size: 18px;
@@ -2138,7 +2044,7 @@
 }
 
 @media (min-width: 40.0625em) {
-  /* line 238, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+  /* line 236, node_modules/govuk-frontend/govuk/components/button/_index.scss */
   .govuk-button--start {
     font-size: 24px;
     font-size: 1.5rem;
@@ -2147,14 +2053,14 @@
 }
 
 @media print {
-  /* line 238, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+  /* line 236, node_modules/govuk-frontend/govuk/components/button/_index.scss */
   .govuk-button--start {
     font-size: 18pt;
     line-height: 1;
   }
 }
 
-/* line 256, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+/* line 254, node_modules/govuk-frontend/govuk/components/button/_index.scss */
 .govuk-button__start-icon {
   margin-left: 5px;
   vertical-align: middle;
@@ -2165,7 +2071,7 @@
 }
 
 @media (min-width: 48.0625em) {
-  /* line 256, node_modules/govuk-frontend/govuk/components/button/_index.scss */
+  /* line 254, node_modules/govuk-frontend/govuk/components/button/_index.scss */
   .govuk-button__start-icon {
     margin-left: 10px;
   }
@@ -3007,95 +2913,15 @@
 
 /* line 16, node_modules/govuk-frontend/govuk/components/character-count/_index.scss */
 .govuk-character-count__message {
-  font-family: "GDS Transport", arial, sans-serif;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-  -webkit-font-feature-settings: "tnum" 1;
-  font-feature-settings: "tnum" 1;
-  font-weight: 400;
   margin-top: 0;
   margin-bottom: 0;
 }
 
-@media print {
-  /* line 16, node_modules/govuk-frontend/govuk/components/character-count/_index.scss */
-  .govuk-character-count__message {
-    font-family: sans-serif;
-  }
-}
-
-@supports (font-variant-numeric: tabular-nums) {
-  /* line 16, node_modules/govuk-frontend/govuk/components/character-count/_index.scss */
-  .govuk-character-count__message {
-    -webkit-font-feature-settings: normal;
-    font-feature-settings: normal;
-    font-variant-numeric: tabular-nums;
-  }
-}
-
-/* line 22, node_modules/govuk-frontend/govuk/components/character-count/_index.scss */
+/* line 21, node_modules/govuk-frontend/govuk/components/character-count/_index.scss */
 .govuk-character-count__message--disabled {
   visibility: hidden;
 }
 
-/* line 6, node_modules/govuk-frontend/govuk/components/cookie-banner/_index.scss */
-.govuk-cookie-banner {
-  font-family: "GDS Transport", arial, sans-serif;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-  font-weight: 400;
-  font-size: 16px;
-  font-size: 1rem;
-  line-height: 1.25;
-  padding-top: 20px;
-  border-bottom: 10px solid transparent;
-  background-color: #f3f2f1;
-}
-
-@media print {
-  /* line 6, node_modules/govuk-frontend/govuk/components/cookie-banner/_index.scss */
-  .govuk-cookie-banner {
-    font-family: sans-serif;
-  }
-}
-
-@media (min-width: 40.0625em) {
-  /* line 6, node_modules/govuk-frontend/govuk/components/cookie-banner/_index.scss */
-  .govuk-cookie-banner {
-    font-size: 19px;
-    font-size: 1.1875rem;
-    line-height: 1.3157894737;
-  }
-}
-
-@media print {
-  /* line 6, node_modules/govuk-frontend/govuk/components/cookie-banner/_index.scss */
-  .govuk-cookie-banner {
-    font-size: 14pt;
-    line-height: 1.15;
-  }
-}
-
-/* line 22, node_modules/govuk-frontend/govuk/components/cookie-banner/_index.scss */
-.govuk-cookie-banner[hidden] {
-  display: none;
-}
-
-/* line 26, node_modules/govuk-frontend/govuk/components/cookie-banner/_index.scss */
-.govuk-cookie-banner__message {
-  margin-bottom: -10px;
-}
-
-/* line 30, node_modules/govuk-frontend/govuk/components/cookie-banner/_index.scss */
-.govuk-cookie-banner__message[hidden] {
-  display: none;
-}
-
-/* line 36, node_modules/govuk-frontend/govuk/components/cookie-banner/_index.scss */
-.govuk-cookie-banner__message:focus {
-  outline: none;
-}
-
 /* line 2, node_modules/govuk-frontend/govuk/components/summary-list/_index.scss */
 .govuk-summary-list {
   font-family: "GDS Transport", arial, sans-serif;
@@ -6230,149 +6056,6 @@
   text-align: left;
 }
 
-/* line 53, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-.govuk-table__caption--xl {
-  font-family: "GDS Transport", arial, sans-serif;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-  font-weight: 700;
-  font-size: 32px;
-  font-size: 2rem;
-  line-height: 1.09375;
-  margin-bottom: 15px;
-}
-
-@media print {
-  /* line 53, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--xl {
-    font-family: sans-serif;
-  }
-}
-
-@media (min-width: 40.0625em) {
-  /* line 53, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--xl {
-    font-size: 48px;
-    font-size: 3rem;
-    line-height: 1.0416666667;
-  }
-}
-
-@media print {
-  /* line 53, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--xl {
-    font-size: 32pt;
-    line-height: 1.15;
-  }
-}
-
-/* line 58, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-.govuk-table__caption--l {
-  font-family: "GDS Transport", arial, sans-serif;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-  font-weight: 700;
-  font-size: 24px;
-  font-size: 1.5rem;
-  line-height: 1.0416666667;
-  margin-bottom: 15px;
-}
-
-@media print {
-  /* line 58, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--l {
-    font-family: sans-serif;
-  }
-}
-
-@media (min-width: 40.0625em) {
-  /* line 58, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--l {
-    font-size: 36px;
-    font-size: 2.25rem;
-    line-height: 1.1111111111;
-  }
-}
-
-@media print {
-  /* line 58, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--l {
-    font-size: 24pt;
-    line-height: 1.05;
-  }
-}
-
-/* line 63, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-.govuk-table__caption--m {
-  font-family: "GDS Transport", arial, sans-serif;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-  font-weight: 700;
-  font-size: 18px;
-  font-size: 1.125rem;
-  line-height: 1.1111111111;
-  margin-bottom: 15px;
-}
-
-@media print {
-  /* line 63, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--m {
-    font-family: sans-serif;
-  }
-}
-
-@media (min-width: 40.0625em) {
-  /* line 63, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--m {
-    font-size: 24px;
-    font-size: 1.5rem;
-    line-height: 1.25;
-  }
-}
-
-@media print {
-  /* line 63, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--m {
-    font-size: 18pt;
-    line-height: 1.15;
-  }
-}
-
-/* line 68, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-.govuk-table__caption--s {
-  font-family: "GDS Transport", arial, sans-serif;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-  font-weight: 700;
-  font-size: 16px;
-  font-size: 1rem;
-  line-height: 1.25;
-}
-
-@media print {
-  /* line 68, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--s {
-    font-family: sans-serif;
-  }
-}
-
-@media (min-width: 40.0625em) {
-  /* line 68, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--s {
-    font-size: 19px;
-    font-size: 1.1875rem;
-    line-height: 1.3157894737;
-  }
-}
-
-@media print {
-  /* line 68, node_modules/govuk-frontend/govuk/components/table/_index.scss */
-  .govuk-table__caption--s {
-    font-size: 14pt;
-    line-height: 1.15;
-  }
-}
-
 /* line 2, node_modules/govuk-frontend/govuk/components/warning-text/_index.scss */
 .govuk-warning-text {
   position: relative;
@@ -11711,10 +11394,10 @@ <h2 class="govuk-heading-l" id="accordion">Accordion</h2>
   <h2 class="govuk-heading-s">Accordion</h2>
   <section>
     <div id="abc123" class="govuk-accordion" data-module="govuk-accordion">
-    <div id="home-electronics-section" class="govuk-accordion__section">
+    <div id="home-electronics-section" class="govuk-accordion__section govuk-accordion__section--expanded">
       <div class="govuk-accordion__section-header">
         <h2 class="govuk-accordion__section-heading">
-          <span id="home-electronics" class="govuk-accordion__section-button">Home electronics</span>
+          <span id="home-electronics" class="govuk-accordion__section-button" aria-expanded="true">Home electronics</span>
         </h2>
           <div id="home-electronics-summary" class="govuk-accordion__section-summary govuk-body">Entertainment, communication and recreation</div>
       </div>
@@ -11722,7 +11405,7 @@ <h2 class="govuk-accordion__section-heading">
 </div>    <div id="appliances-section" class="govuk-accordion__section">
       <div class="govuk-accordion__section-header">
         <h2 class="govuk-accordion__section-heading">
-          <span id="appliances" class="govuk-accordion__section-button">Appliances</span>
+          <span id="appliances" class="govuk-accordion__section-button" aria-expanded="false">Appliances</span>
         </h2>
           <div id="appliances-summary" class="govuk-accordion__section-summary govuk-body">Laundry, cookers and vacuum cleaners</div>
       </div>
@@ -11730,7 +11413,7 @@ <h2 class="govuk-accordion__section-heading">
 </div>    <div id="toys-section" class="govuk-accordion__section">
       <div class="govuk-accordion__section-header">
         <h2 class="govuk-accordion__section-heading">
-          <span id="toys" class="govuk-accordion__section-button">Toys</span>
+          <span id="toys" class="govuk-accordion__section-button" aria-expanded="false">Toys</span>
         </h2>
       </div>
       <div id="toys-content" class="govuk-accordion__section-content" aria-labelledby="toys">
@@ -11744,7 +11427,8 @@ <h2 class="govuk-accordion__section-heading">
     <pre><code class="language-ruby">render GovukComponent::Accordion.new(id: 'abc123') do |component|
   component.slot(:section,
     title: 'Home electronics',
-    summary: 'Entertainment, communication and recreation') do
+    summary: 'Entertainment, communication and recreation',
+    expanded: true) do
       tag.p(class: 'govuk-body') do
         "Lorem ipsum dolor sit amet, consectetur adipiscing elit."
       end
@@ -11781,21 +11465,21 @@ <h2 class="govuk-heading-s">Accordion (using the helper)</h2>
     <div id="section-1-section" class="govuk-accordion__section">
       <div class="govuk-accordion__section-header">
         <h2 class="govuk-accordion__section-heading">
-          <span id="section-1" class="govuk-accordion__section-button">Section 1</span>
+          <span id="section-1" class="govuk-accordion__section-button" aria-expanded="false">Section 1</span>
         </h2>
       </div>
       <div id="section-1-content" class="govuk-accordion__section-content" aria-labelledby="section-1"><p class="govuk-body">Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p></div>
-</div>    <div id="section-2-section" class="govuk-accordion__section">
+</div>    <div id="section-2-section" class="govuk-accordion__section govuk-accordion__section--expanded">
       <div class="govuk-accordion__section-header">
         <h2 class="govuk-accordion__section-heading">
-          <span id="section-2" class="govuk-accordion__section-button">Section 2</span>
+          <span id="section-2" class="govuk-accordion__section-button" aria-expanded="true">Section 2</span>
         </h2>
       </div>
       <div id="section-2-content" class="govuk-accordion__section-content" aria-labelledby="section-2"><p class="govuk-body">Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p></div>
 </div>    <div id="section-3-section" class="govuk-accordion__section">
       <div class="govuk-accordion__section-header">
         <h2 class="govuk-accordion__section-heading">
-          <span id="section-3" class="govuk-accordion__section-button">Section 3</span>
+          <span id="section-3" class="govuk-accordion__section-button" aria-expanded="false">Section 3</span>
         </h2>
       </div>
       <div id="section-3-content" class="govuk-accordion__section-content" aria-labelledby="section-3"><p class="govuk-body">Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p></div>
@@ -11809,7 +11493,7 @@ <h2 class="govuk-accordion__section-heading">
       "Lorem ipsum dolor sit amet, consectetur adipiscing elit."
     end
   end
-  accordion.add_section(title: 'Section 2') do
+  accordion.add_section(title: 'Section 2', expanded: true) do
     tag.p(class: 'govuk-body') do
       "Lorem ipsum dolor sit amet, consectetur adipiscing elit."
     end
@@ -11964,27 +11648,27 @@ <h2 class="govuk-heading-l" id="cookie-banner">Cookie banner</h2>
 <article class="example govuk-!-margin-top-9" id="cookie-banner">
   <h2 class="govuk-heading-s">Cookie banner</h2>
   <section>
-    <div class="govuk-cookie-banner">
+    <div class="govuk-cookie-banner" role="region" aria-label="Cookie banner">
   <div class="govuk-cookie-banner__message govuk-width-container">
     <div class="govuk-grid-row">
       <div class="govuk-grid-column-two-thirds">
-        <h2 class="govuk-cookie-banner__heading govuk-heading-m">
-          Cookies on a service
-        </h2>
+          <h2 class="govuk-cookie-banner__heading govuk-heading-m">
+            Cookies on a service
+          </h2>
 
         <div class="govuk-cookie-banner__content">
           <p class="govuk-body">A paragraph.</p>
-<p class="govuk-body-s">A second smaller paragraph.</p>
+<p class="govuk-body-s">A second, smaller paragraph.</p>
         </div>
       </div>
     </div>
 
     <div class="govuk-button-group">
       <form class="button_to" method="post" action="#accept">
-<input class="govuk-button" type="submit" value="Accept cookies"><input type="hidden" name="authenticity_token" value="t+ABJ+rztwK0g+usl86yYWTZWXBHpbLgXnKFMd8ZwPISbN7TlfdqDpFWTT0XEmvkTBvFJrh/vXuWwji7ZxPIJQ==">
+<input class="govuk-button" type="submit" value="Accept cookies"><input type="hidden" name="authenticity_token" value="CKjvcm5XqxTbQVwAFOibImAnm2fMS9Z/qtH/tHMzbBwKEY5R9W94YX5AwxeZ28SZJGWW4ag5gK9yrC38J20tRQ==">
 </form>
 <form class="button_to" method="post" action="#reject">
-<input class="govuk-button" type="submit" value="Reject cookies"><input type="hidden" name="authenticity_token" value="WxYDihHQ1LLg2WzQ9ksna6QgrEu2rB/ClwZWDobubsv+mtx+btQJvsUMykF2l/7ujOIwHUl2EFlftuuEPuRmHA==">
+<input class="govuk-button" type="submit" value="Reject cookies"><input type="hidden" name="authenticity_token" value="7AQWnal+m1Jb+JrDUDq54o6DDDdPS/2x3JsD7uJtPgnuvXe+MkZIJ/75BdTdCeZZysEBsSs5q2EE5tGmtjN/UA==">
 </form>
 <a class="govuk-link" href="#view">View cookies</a>
     </div>
@@ -11992,11 +11676,11 @@ <h2 class="govuk-cookie-banner__heading govuk-heading-m">
 </div>
   </section>
   <section>
-    <pre><code class="language-ruby">render GovukComponent::CookieBanner.new(title: 'Cookies on a service') do |component|
+    <pre><code class="language-ruby">render GovukComponent::CookieBanner.new(title: "Cookies on a service") do |component|
   component.with(:body) do
     safe_join([
       tag.p("A paragraph.", class: "govuk-body"),
-      tag.p("A second smaller paragraph.", class: "govuk-body-s"),
+      tag.p("A second, smaller paragraph.", class: "govuk-body-s"),
     ])
   end
   component.with(:actions) do
@@ -12351,7 +12035,7 @@ <h2 class="govuk-heading-s">Email links</h2>
   <h2 class="govuk-heading-s">Button links (this will render a form that POSTs)</h2>
   <section>
     <form class="button_to" method="post" action="/">
-<input class="govuk-button" type="submit" value="Home"><input type="hidden" name="authenticity_token" value="gx/bn3yShVvku3Mt6aAPrCuSNhHGt1kb3teb9Nx390gmkwRrA5ZYV8Fu1bxpfNYpA1CqRzltVoAWZyZ+ZH3/nw==">
+<input class="govuk-button" type="submit" value="Home"><input type="hidden" name="authenticity_token" value="Qjxo4uRrD107rr9n3YXCDKDowzyiGPSjZ8A5Im8wD2pAhQnBf1PcKJ6vIHBQtp235KrOusZqonO/vetqO25OMw==">
 </form>
   </section>
   <section>
diff --git a/spec/components/govuk_component/accordion_spec.rb b/spec/components/govuk_component/accordion_spec.rb
index f3742d4f..09cca90c 100644
--- a/spec/components/govuk_component/accordion_spec.rb
+++ b/spec/components/govuk_component/accordion_spec.rb
@@ -88,6 +88,18 @@
 
     it_behaves_like 'a component with a slot that accepts custom classes'
     it_behaves_like 'a component with a slot that accepts custom html attributes'
+
+    it 'sections should have correct expanded state' do
+      render_inline(GovukComponent::Accordion.new) do |component|
+        component.slot(:section, expanded: true, title: 'section 1', html_attributes: { id: 'section_1' }) { 'abc' }
+        component.slot(:section, title: 'section 2', html_attributes: { id: 'section_2' }) { 'def' }
+      end
+      expect(page).to have_css('#section_1.govuk-accordion__section.govuk-accordion__section--expanded')
+      expect(page).to have_css('#section_2.govuk-accordion__section')
+      expect(page).not_to have_css('#section_2.govuk-accordion__section.govuk-accordion__section--expanded')
+      expect(page).to have_css('span#section-1[aria-expanded="true"]')
+      expect(page).to have_css('span#section-2[aria-expanded="false"]')
+    end
   end
 
   it_behaves_like 'a component with a DSL wrapper' do
diff --git a/spec/dummy/app/views/demos/examples/_accordion.html.erb b/spec/dummy/app/views/demos/examples/_accordion.html.erb
index ae565016..57a2ca91 100644
--- a/spec/dummy/app/views/demos/examples/_accordion.html.erb
+++ b/spec/dummy/app/views/demos/examples/_accordion.html.erb
@@ -4,7 +4,8 @@
   render GovukComponent::Accordion.new(id: 'abc123') do |component|
     component.slot(:section,
       title: 'Home electronics',
-      summary: 'Entertainment, communication and recreation') do
+      summary: 'Entertainment, communication and recreation',
+      expanded: true) do
         tag.p(class: 'govuk-body') do
           "Lorem ipsum dolor sit amet, consectetur adipiscing elit."
         end
@@ -39,7 +40,7 @@
         "Lorem ipsum dolor sit amet, consectetur adipiscing elit."
       end
     end
-    accordion.add_section(title: 'Section 2') do
+    accordion.add_section(title: 'Section 2', expanded: true) do
       tag.p(class: 'govuk-body') do
         "Lorem ipsum dolor sit amet, consectetur adipiscing elit."
       end