diff --git a/app/controllers/content_items_controller.rb b/app/controllers/content_items_controller.rb
index 3e1eb83c8..63ecf2a98 100644
--- a/app/controllers/content_items_controller.rb
+++ b/app/controllers/content_items_controller.rb
@@ -92,6 +92,10 @@ def load_content_item
       content_item["links"]["ordered_related_items"] = content_item["links"].fetch("suggested_ordered_related_items", [])
     end
 
+    if update_brexit_navigation?(content_item)
+      content_item["links"]["taxons"] = taxons_updated_for_brexit_test(content_item)
+    end
+
     @content_item = PresenterBuilder.new(
       content_item,
       content_item_path,
@@ -99,6 +103,21 @@ def load_content_item
     ).presenter
   end
 
+  def update_brexit_navigation?(content_item)
+    content_item["content_id"] == "7a616597-c921-47ba-bd50-7e73449e140b" # /visit-europe-1-january-2021
+  end
+
+  def taxons_updated_for_brexit_test(content_item)
+    content_item["links"]["taxons"].map do |taxon|
+      taxon["title"] = "The UK and EU transition: new rules for 2021" if brexit_taxon?(taxon)
+      taxon
+    end
+  end
+
+  def brexit_taxon?(taxon)
+    taxon["content_id"] == "d6c2de5d-ef90-45d1-82d4-5f2438369eea"
+  end
+
   def format_banner_links(links, type)
     links.each.with_index(1).map do |(title, base_path), index|
       view_context.link_to(
diff --git a/test/integration/guide_test.rb b/test/integration/guide_test.rb
index 47cbd75b9..2435a8ff5 100644
--- a/test/integration/guide_test.rb
+++ b/test/integration/guide_test.rb
@@ -112,6 +112,35 @@ class GuideTest < ActionDispatch::IntegrationTest
     assert_nil faq_schema
   end
 
+  test "a specific guide has tweaked Brexit navigation" do
+    visit_europe_guide_id = "7a616597-c921-47ba-bd50-7e73449e140b"
+    setup_and_visit_a_guide_with_the_brexit_taxon(visit_europe_guide_id)
+
+    assert page.has_css?(".gem-c-step-nav-header__title", text: "The UK and EU transition: new rules for 2021")
+  end
+
+  test "a normal Brexit guide has normal Brexit navigation" do
+    setup_and_visit_a_guide_with_the_brexit_taxon
+
+    assert page.has_css?(".gem-c-step-nav-header__title", text: "Brexit things")
+  end
+
+  def setup_and_visit_a_guide_with_the_brexit_taxon(content_id = nil)
+    @content_item = get_content_example("guide").tap do |item|
+      item["content_id"] = content_id if content_id.present?
+      item["links"]["taxons"] = [brexit_taxon]
+      stub_content_store_has_item(item["base_path"], item.to_json)
+      visit_with_cachebust(item["base_path"])
+    end
+  end
+
+  def brexit_taxon
+    @brexit_taxon ||= GovukSchemas::Example.find("taxon", example_name: "taxon").tap do |taxon|
+      taxon["title"] = "Brexit things"
+      taxon["content_id"] = "d6c2de5d-ef90-45d1-82d4-5f2438369eea" # the real Brexit taxon ID
+    end
+  end
+
   def setup_and_visit_part_in_guide
     @content_item = get_content_example("guide").tap do |item|
       chapter_path = "#{item['base_path']}/key-stage-1-and-2"