diff --git a/app/main/forms.py b/app/main/forms.py
index 016534ed4..f22053df7 100644
--- a/app/main/forms.py
+++ b/app/main/forms.py
@@ -418,6 +418,7 @@ PermissionsAbstract = type("PermissionsAbstract", (StripWhitespaceForm,), {
 class PermissionsForm(PermissionsAbstract):
     def __init__(self, all_template_folders=None, *args, **kwargs):
         super().__init__(*args, **kwargs)
+        self.folder_permissions.choices = []
         if all_template_folders is not None:
             self.folder_permissions.all_template_folders = all_template_folders
             self.folder_permissions.choices = [
diff --git a/app/main/views/manage_users.py b/app/main/views/manage_users.py
index 314c18755..4c38a79ce 100644
--- a/app/main/views/manage_users.py
+++ b/app/main/views/manage_users.py
@@ -103,11 +103,11 @@ def edit_user_permissions(service_id, user_id):
     form = PermissionsForm.from_user(
         user,
         service_id,
-        folder_permissions=[
+        folder_permissions=None if user.platform_admin else [
             f['id'] for f in current_service.all_template_folders
             if user.has_template_folder_permission(f)
         ],
-        all_template_folders=current_service.all_template_folders
+        all_template_folders=None if user.platform_admin else current_service.all_template_folders
     )
 
     if form.validate_on_submit():
diff --git a/app/templates/views/manage-users/permissions.html b/app/templates/views/manage-users/permissions.html
index 8d839b9aa..a3b0160fd 100644
--- a/app/templates/views/manage-users/permissions.html
+++ b/app/templates/views/manage-users/permissions.html
@@ -15,6 +15,10 @@
 
 {% if current_service.has_permission("edit_folder_permissions") and form.folder_permissions.all_template_folders %}
   {{ checkboxes_nested(form.folder_permissions, form.folder_permissions.children(), hide_legend=True, collapsible_opts={ 'field': 'folder' }) }}
+{% elif user and user.platform_admin %}
+  <p class="bottom-gutter">
+    Platform admin users can access all template folders.
+  </p>
 {% endif %}
 
 {% if service_has_email_auth %}
diff --git a/tests/app/main/views/test_manage_users.py b/tests/app/main/views/test_manage_users.py
index 2d45c8b02..6f2c19f4e 100644
--- a/tests/app/main/views/test_manage_users.py
+++ b/tests/app/main/views/test_manage_users.py
@@ -17,6 +17,7 @@ from tests.conftest import (
     active_user_view_permissions,
     active_user_with_permissions,
     normalize_spaces,
+    platform_admin_user,
     sample_uuid,
 )
 
@@ -478,6 +479,18 @@ def test_edit_user_folder_permissions(
         {'id': 'folder-id-2', 'name': 'folder_one', 'parent_id': None, 'users_with_permission': []},
         {'id': 'folder-id-3', 'name': 'folder_one', 'parent_id': 'folder-id-1', 'users_with_permission': []},
     ]
+
+    page = client_request.get(
+        'main.edit_user_permissions',
+        service_id=SERVICE_ONE_ID,
+        user_id=fake_uuid,
+    )
+    assert [
+        item['value'] for item in page.select('input[name=folder_permissions]')
+    ] == [
+        'folder-id-1', 'folder-id-3', 'folder-id-2'
+    ]
+
     client_request.post(
         'main.edit_user_permissions',
         service_id=SERVICE_ONE_ID,
@@ -500,6 +513,57 @@ def test_edit_user_folder_permissions(
     )
 
 
+def test_cant_edit_user_folder_permissions_for_platform_admin_users(
+    client_request,
+    mocker,
+    service_one,
+    mock_get_users_by_service,
+    mock_get_invites_for_service,
+    mock_set_user_permissions,
+    mock_get_template_folders,
+    fake_uuid,
+):
+    service_one['permissions'] = ['edit_folder_permissions']
+    mocker.patch(
+        'app.user_api_client.get_user', return_value=platform_admin_user(fake_uuid)
+    )
+    mock_get_template_folders.return_value = [
+        {'id': 'folder-id-1', 'name': 'folder_one', 'parent_id': None, 'users_with_permission': []},
+        {'id': 'folder-id-2', 'name': 'folder_one', 'parent_id': None, 'users_with_permission': []},
+        {'id': 'folder-id-3', 'name': 'folder_one', 'parent_id': 'folder-id-1', 'users_with_permission': []},
+    ]
+    page = client_request.get(
+        'main.edit_user_permissions',
+        service_id=SERVICE_ONE_ID,
+        user_id=fake_uuid,
+    )
+    assert normalize_spaces(page.select('main p')[0].text) == 'platform@admin.gov.uk Change'
+    assert normalize_spaces(page.select('main p')[2].text) == (
+        'Platform admin users can access all template folders.'
+    )
+    assert page.select('input[name=folder_permissions]') == []
+    client_request.post(
+        'main.edit_user_permissions',
+        service_id=SERVICE_ONE_ID,
+        user_id=fake_uuid,
+        _data={},
+        _expected_status=302,
+        _expected_redirect=url_for(
+            'main.manage_users',
+            service_id=SERVICE_ONE_ID,
+            _external=True,
+        ),
+    )
+    mock_set_user_permissions.assert_called_with(
+        fake_uuid,
+        SERVICE_ONE_ID,
+        permissions={
+            'manage_api_keys', 'manage_service', 'manage_templates', 'send_messages', 'view_activity',
+        },
+        folder_permissions=None,
+    )
+
+
 def test_cant_edit_non_member_user_permissions(
     client_request,
     mocker,