diff --git a/app/assets/javascripts/main.js b/app/assets/javascripts/main.js
index e48485471..b130c050b 100644
--- a/app/assets/javascripts/main.js
+++ b/app/assets/javascripts/main.js
@@ -1,27 +1,38 @@
-window.GOVUK.Frontend.initAll();
-
-$(() => $("time.timeago").timeago());
+// Initialize GOV.UK Frontend components (modern init)
+window.GOVUKFrontend.initAll();
 
 var showHideContent = new GOVUK.ShowHideContent();
 showHideContent.init();
 
-$(() => GOVUK.modules.start());
-
-$(() => $('.error-message, .usa-error-message').eq(0).parent('label').next('input').trigger('focus'));
-
-$(() => $('.govuk-header__container').on('click', function() {
-  $(this).css('border-color', '#005ea5');
-}));
-
-// Applies our expanded focus style to the siblings of links when that link is wrapped in a heading.
-//
-// This will be possible in CSS in the future, using the :has pseudo-class. When :has is available
-// in the browsers we support, this code can be replaced with a CSS-only solution.
-$('.js-mark-focus-on-parent').on('focus blur', '*', e => {
-  $target = $(e.target);
-  if (e.type === 'focusin') {
-    $target.parent().addClass('js-child-has-focus');
-  } else {
-    $target.parent().removeClass('js-child-has-focus');
+document.addEventListener('DOMContentLoaded', () => {
+  // Autofocus the first error input
+  const errorEl = document.querySelector('.error-message, .usa-error-message');
+  if (errorEl) {
+    const label = errorEl.closest('label');
+    if (label) {
+      const input = label.nextElementSibling;
+      if (input && input.focus) {
+        input.focus();
+      }
+    }
   }
+
+  // Optional: highlight header on click
+  const header = document.querySelector('.govuk-header__container');
+  if (header) {
+    header.addEventListener('click', () => {
+      header.style.borderColor = '#005ea5';
+    });
+  }
+
+  // Focus styling for heading-wrapped links
+  const containers = document.querySelectorAll('.js-mark-focus-on-parent');
+  containers.forEach(container => {
+    container.addEventListener('focusin', e => {
+      e.target.parentElement.classList.add('js-child-has-focus');
+    });
+    container.addEventListener('focusout', e => {
+      e.target.parentElement.classList.remove('js-child-has-focus');
+    });
+  });
 });
diff --git a/app/templates/views/api/index.html b/app/templates/views/api/index.html
index 0bd3e2a94..cf295c0c0 100644
--- a/app/templates/views/api/index.html
+++ b/app/templates/views/api/index.html
@@ -57,7 +57,7 @@
                 {{notification.key_name}}
               </span>
               <span class="grid-col-6 api-notifications-item__meta-time">
-                <time class="timeago" datetime="{{ notification.created_at }}">
+                <time datetime="{{ notification.created_at }}">
                   {{ notification.created_at|format_delta }}
                 </time>
               </span>
diff --git a/app/templates/views/find-users/user-information.html b/app/templates/views/find-users/user-information.html
index 3a90b7bc6..4575f4748 100644
--- a/app/templates/views/find-users/user-information.html
+++ b/app/templates/views/find-users/user-information.html
@@ -60,7 +60,7 @@
       <p class="hint">This person has never logged in</p>
       {% else %}
       <p>Last logged in
-        <time class="timeago" datetime="{{ user.logged_in_at }}">
+        <time datetime="{{ user.logged_in_at }}">
           {{ user.logged_in_at|format_delta }}
         </time>
       </p>
diff --git a/gulpfile.js b/gulpfile.js
index f360747b2..5e8f3ab32 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -47,7 +47,6 @@ const javascripts = () => {
         paths.npm + 'hogan.js/dist/hogan-3.0.2.js',
         paths.npm + 'jquery/dist/jquery.min.js',
         paths.npm + 'query-command-supported/dist/queryCommandSupported.min.js',
-        paths.npm + 'timeago/jquery.timeago.js',
         paths.npm + 'textarea-caret/index.js',
         paths.npm + 'cbor-js/cbor.js',
         paths.npm + 'd3/dist/d3.min.js',
diff --git a/package-lock.json b/package-lock.json
index 0c71924da..b1c514b65 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -26,7 +26,6 @@
         "query-command-supported": "1.0.0",
         "sass-embedded": "^1.86.3",
         "textarea-caret": "3.1.0",
-        "timeago": "1.6.7",
         "vinyl-buffer": "^1.0.1",
         "vinyl-source-stream": "^2.0.0"
       },
@@ -12680,14 +12679,6 @@
         "node": ">=0.10.0"
       }
     },
-    "node_modules/timeago": {
-      "version": "1.6.7",
-      "resolved": "https://registry.npmjs.org/timeago/-/timeago-1.6.7.tgz",
-      "integrity": "sha512-FikcjN98+ij0siKH4VO4dZ358PR3oDDq4Vdl1+sN9gWz1/+JXGr3uZbUShYH/hL7bMhcTpPbplJU5Tej4b4jbQ==",
-      "dependencies": {
-        "jquery": ">=1.5.0 <4.0"
-      }
-    },
     "node_modules/tmpl": {
       "version": "1.0.5",
       "resolved": "https://registry.npmjs.org/tmpl/-/tmpl-1.0.5.tgz",
diff --git a/package.json b/package.json
index bed81b47c..3eed62930 100644
--- a/package.json
+++ b/package.json
@@ -42,7 +42,6 @@
     "query-command-supported": "1.0.0",
     "sass-embedded": "^1.86.3",
     "textarea-caret": "3.1.0",
-    "timeago": "1.6.7",
     "vinyl-buffer": "^1.0.1",
     "vinyl-source-stream": "^2.0.0"
   },
diff --git a/poetry.lock b/poetry.lock
index 1d0262110..a23a0e07c 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -17,7 +17,6 @@ version = "5.0.1"
 description = "Timeout context manager for asyncio programs"
 optional = false
 python-versions = ">=3.8"
-groups = ["main"]
 files = [
     {file = "async_timeout-5.0.1-py3-none-any.whl", hash = "sha256:39e3809566ff85354557ec2398b55e096c8364bacac9405a7a1fa429e77fe76c"},
     {file = "async_timeout-5.0.1.tar.gz", hash = "sha256:d9321a7a3d5a6a5e187e824d2fa0793ce379a202935782d555d6e9d2735677d3"},
@@ -1486,7 +1485,6 @@ version = "3.0.2"
 description = "Safely add untrusted strings to HTML/XML markup."
 optional = false
 python-versions = ">=3.9"
-groups = ["main", "dev"]
 files = [
     {file = "MarkupSafe-3.0.2-cp310-cp310-macosx_10_9_universal2.whl", hash = "sha256:7e94c425039cde14257288fd61dcfb01963e658efbc0ff54f5306b06054700f8"},
     {file = "MarkupSafe-3.0.2-cp310-cp310-macosx_11_0_arm64.whl", hash = "sha256:9e2d922824181480953426608b81967de705c3cef4d1af983af849d7bd619158"},
diff --git a/tests/javascripts/main.test.js b/tests/javascripts/main.test.js
new file mode 100644
index 000000000..e69de29bb