diff --git a/lib/assets/javascripts/_modules/table-of-contents.js b/lib/assets/javascripts/_modules/table-of-contents.js
index 32229f48..ea703493 100644
--- a/lib/assets/javascripts/_modules/table-of-contents.js
+++ b/lib/assets/javascripts/_modules/table-of-contents.js
@@ -104,7 +104,6 @@
     function openNavigation () {
       $html.addClass('toc-open')
 
-      toggleBackgroundVisiblity(false)
       updateAriaAttributes()
       $toc.focus()
     }
@@ -112,26 +111,30 @@
     function closeNavigation () {
       $html.removeClass('toc-open')
 
-      toggleBackgroundVisiblity(true)
-      $openButton.focus()
       updateAriaAttributes()
-    }
-
-    function toggleBackgroundVisiblity (visibility) {
-      $('.toc-open-disabled').attr('aria-hidden', visibility ? '' : 'true')
+      $openButton.focus()
     }
 
     function updateAriaAttributes () {
       var tocIsVisible = $toc.is(':visible')
-      var openButtonIsVisible = $openButton.is(':visible')
+      var tocIsDialog = $openButton.is(':visible')
 
       $($openButton).add($closeButton)
         .attr('aria-expanded', tocIsVisible ? 'true' : 'false')
 
       $toc.attr({
         'aria-hidden': tocIsVisible ? 'false' : 'true',
-        role: openButtonIsVisible ? 'dialog' : null
+        role: tocIsDialog ? 'dialog' : null
       })
+
+      $('.app-pane__content').attr('aria-hidden', (tocIsDialog && tocIsVisible) ? 'true' : 'false')
+
+      // only make main content pane focusable if it scrolls independently of the toc
+      if (!tocIsDialog) {
+        $('.app-pane__content').attr('tabindex', '0')
+      } else {
+        $('.app-pane__content').removeAttr('tabindex')
+      }
     }
 
     function preventingScrolling (callback) {
diff --git a/lib/assets/stylesheets/modules/_app-pane.scss b/lib/assets/stylesheets/modules/_app-pane.scss
index 9e82194c..1874a2c8 100644
--- a/lib/assets/stylesheets/modules/_app-pane.scss
+++ b/lib/assets/stylesheets/modules/_app-pane.scss
@@ -61,3 +61,10 @@
   }
 }
 
+.app-pane__content:focus-visible,
+.app-pane__content:has(main:focus-visible) {
+  outline: $govuk-focus-width solid transparent;
+  box-shadow:
+    0 0 0 4px $govuk-focus-colour,
+    0 0 0 8px $govuk-focus-text-colour;
+}
diff --git a/lib/source/layouts/core.erb b/lib/source/layouts/core.erb
index d86aa1d3..499083dd 100644
--- a/lib/source/layouts/core.erb
+++ b/lib/source/layouts/core.erb
@@ -58,7 +58,7 @@
           </div>
         <% end %>
 
-        <div class="app-pane__content toc-open-disabled" aria-label="Content" tabindex="0">
+        <div class="app-pane__content toc-open-disabled" aria-label="Content">
           <main id="content" class="technical-documentation" data-module="anchored-headings">
             <%= yield %>
             <%= partial "layouts/page_review" %>
diff --git a/spec/javascripts/table-of-contents-spec.js b/spec/javascripts/table-of-contents-spec.js
index c750c302..dc9412a3 100644
--- a/spec/javascripts/table-of-contents-spec.js
+++ b/spec/javascripts/table-of-contents-spec.js
@@ -5,6 +5,7 @@ describe('Table of contents', function () {
   var $html
   var $tocBase
   var $toc
+  var $mainContentPane
   var $closeButton
   var $openButton
   var $tocStickyHeader
@@ -13,28 +14,33 @@ describe('Table of contents', function () {
   beforeAll(function () {
     $html = $('html')
     $tocBase = $(
-      '<div class="toc" data-module="table-of-contents" tabindex="-1" aria-label="Table of contents">' +
-        '<div class="search" data-module="search" data-path-to-site-root="/">' +
-          '<form action="/search/index.html" method="get" role="search" class="search__form govuk-!-margin-bottom-4">' +
-            '<label class="govuk-label search__label" for="search">Search this documentation</label>' +
-            '<input type="text" id="search" name="q" class="govuk-input govuk-!-margin-bottom-0 search__input" aria-controls="search-results" placeholder="Search">' +
-            '<button type="submit" class="search__button">Search</button>' +
-          '</form>' +
+      '<div class="app-pane__toc">' +
+        '<div class="toc" data-module="table-of-contents" tabindex="-1" aria-label="Table of contents">' +
+          '<div class="search" data-module="search" data-path-to-site-root="/">' +
+            '<form action="/search/index.html" method="get" role="search" class="search__form govuk-!-margin-bottom-4">' +
+              '<label class="govuk-label search__label" for="search">Search this documentation</label>' +
+              '<input type="text" id="search" name="q" class="govuk-input govuk-!-margin-bottom-0 search__input" aria-controls="search-results" placeholder="Search">' +
+              '<button type="submit" class="search__button">Search</button>' +
+            '</form>' +
+          '</div>' +
+          '<button type="button" class="toc__close js-toc-close" aria-controls="toc" aria-label="Hide table of contents"></button>' +
+          '<nav id="toc" class="js-toc-list toc__list" aria-labelledby="toc-heading" data-module="collapsible-navigation">' +
+            '<ul>' +
+              '<li>' +
+                '<a href="/"><span>Technical Documentation Template</span></a>' +
+              '</li>' +
+              '<li>' +
+                '<a href="/"><span>Get started</span></a>' +
+              '</li>' +
+              '<li>' +
+                '<a href="/"><span>Configure your documentation site</span></a>' +
+              '</li>' +
+            '</ul>' +
+          '</nav>' +
         '</div>' +
-        '<button type="button" class="toc__close js-toc-close" aria-controls="toc" aria-label="Hide table of contents"></button>' +
-        '<nav id="toc" class="js-toc-list toc__list" aria-labelledby="toc-heading" data-module="collapsible-navigation">' +
-          '<ul>' +
-            '<li>' +
-              '<a href="/"><span>Technical Documentation Template</span></a>' +
-            '</li>' +
-            '<li>' +
-              '<a href="/"><span>Get started</span></a>' +
-            '</li>' +
-            '<li>' +
-              '<a href="/"><span>Configure your documentation site</span></a>' +
-            '</li>' +
-          '</ul>' +
-        '</nav>' +
+      '</div>' +
+      '<div class="app-pane__content toc-open-disabled" aria-label="content">' +
+        '<main id="content"></main>' +
       '</div>'
     )
 
@@ -51,7 +57,7 @@ describe('Table of contents', function () {
   })
 
   beforeEach(function () {
-    $toc = $tocBase.clone()
+    var $tocClone = $tocBase.clone()
 
     $html.find('body')
       .append(
@@ -61,8 +67,10 @@ describe('Table of contents', function () {
           '</button>' +
         '</div>'
       )
-      .append($toc)
+      .append($tocClone)
 
+    $toc = $tocClone.eq(0).find('.toc')
+    $mainContentPane = $tocClone.eq(1)
     $closeButton = $toc.find('.js-toc-close')
     $openButton = $html.find('.js-toc-show')
 
@@ -73,14 +81,15 @@ describe('Table of contents', function () {
     // clear up any classes left on <html>
     $html.removeClass('toc-open')
     $html.find('body #toc-heading').remove()
-    $html.find('body .toc').remove()
+    $html.find('body .app-pane__toc').remove()
+    $html.find('body .app-pane__content').remove()
     if ($tocStickyHeader && $tocStickyHeader.length) {
       $tocStickyHeader.remove()
     }
   })
 
   describe('when the module is started', function () {
-    it('on a mobile-size screen, it should mark the table of contents as hidden', function () {
+    it('on a mobile-size screen, it should hide the table of contents and stop the main content pane being focusable', function () {
       // styles applied by this test simulate the styles media-queries will apply on real web pages
       // the .mobile-size class hides the table of contents and the open button
       $html.addClass('mobile-size') // simulate the styles media-queries will apply on real web pages
@@ -89,11 +98,12 @@ describe('Table of contents', function () {
       module.start($toc)
 
       expect($toc.attr('aria-hidden')).toEqual('true')
+      expect($mainContentPane.get(0).hasAttribute('tabindex')).toBe(false)
 
       $html.removeClass('mobile-size')
     })
 
-    it('on a desktop-size screen, it should mark the table of contents as visible', function () {
+    it('on a desktop-size screen, it should show the table of contents and make the main content pane focusable', function () {
       // styles applied by this test simulate the styles media-queries will apply on real web pages
       // by default, they show the table of contents
 
@@ -101,6 +111,7 @@ describe('Table of contents', function () {
       module.start($toc)
 
       expect($toc.attr('aria-hidden')).toEqual('false')
+      expect($mainContentPane.attr('tabindex')).toEqual('0')
     })
   })
 
@@ -156,10 +167,15 @@ describe('Table of contents', function () {
 
   describe('if the open button is clicked', function () {
     beforeEach(function () {
+      $html.addClass('mobile-size')
       module = new GOVUK.Modules.TableOfContents()
       module.start($toc)
     })
 
+    afterEach(function () {
+      $html.removeClass('toc-open mobile-size')
+    })
+
     it('the click event should be cancelled', function () {
       var clickEvt = new $.Event('click')
 
@@ -168,7 +184,7 @@ describe('Table of contents', function () {
       expect(clickEvt.isDefaultPrevented()).toBe(true)
     })
 
-    it('the table of contents should show and be focused', function () {
+    it('the table of contents should show and be focused and the main content hidden', function () {
       // detecting focus has proved unreliable so track calls to $toc.focus instead
       var _focus = $.fn.focus
       var tocFocusSpy = jasmine.createSpy('tocFocusSpy')
@@ -188,6 +204,7 @@ describe('Table of contents', function () {
       $openButton.trigger(clickEvt)
 
       expect($toc.attr('aria-hidden')).toEqual('false')
+      expect($mainContentPane.attr('aria-hidden')).toEqual('true')
 
       expect(tocFocusSpy).toHaveBeenCalled()
 
@@ -229,9 +246,13 @@ describe('Table of contents', function () {
     it('the button that triggered the dialog is refocused', function () {
       expect(document.activeElement).toBe($openButton.get(0))
     })
+
+    it('the main content area should be shown', function () {
+      expect($mainContentPane.attr('aria-hidden')).toEqual('false')
+    })
   })
 
-  it('on mobile-size screens, when the table of contents is open and the escape key is activated, the table of contents should be hidden', function () {
+  it('on mobile-size screens, when the table of contents is open and the escape key is activated, the table of contents should be hidden and the main content shown', function () {
     $html.addClass('mobile-size')
 
     module = new GOVUK.Modules.TableOfContents()
@@ -244,6 +265,8 @@ describe('Table of contents', function () {
     }))
 
     expect($html.hasClass('toc-open')).toBe(false)
+    expect($toc.attr('aria-hidden')).toEqual('true')
+    expect($mainContentPane.attr('aria-hidden')).toEqual('false')
 
     $html.removeClass('mobile-size')
   })