diff --git a/elasticsearch.yml b/elasticsearch.yml
index e495d6f2f..dd1c4c37e 100644
--- a/elasticsearch.yml
+++ b/elasticsearch.yml
@@ -3,7 +3,6 @@ production: &default
   content_index_names: ["government"]
   govuk_index_name: "govuk"
   auxiliary_index_names: ["page-traffic", "metasearch"]
-  registry_index: "government"
   metasearch_index_name: "metasearch"
   page_traffic_index_name: "page-traffic"
   popularity_rank_offset: 10
@@ -21,7 +20,6 @@ test:
   content_index_names: ["government_test"]
   govuk_index_name: "govuk_test"
   auxiliary_index_names: ["page-traffic_test", "metasearch_test"]
-  registry_index: "government_test"
   metasearch_index_name: "metasearch_test"
   page_traffic_index_name: "page-traffic_test"
   popularity_rank_offset: 10
diff --git a/lib/search/presenters/entity_expander.rb b/lib/search/presenters/entity_expander.rb
index 853c22541..efac78f40 100644
--- a/lib/search/presenters/entity_expander.rb
+++ b/lib/search/presenters/entity_expander.rb
@@ -31,10 +31,8 @@ def initialize(registry_name, new_field_name: nil)
     end
 
     MAPPINGS = [
-      Mapping.new(:document_series),
       Mapping.new(:document_collections),
       Mapping.new(:organisations),
-      Mapping.new(:policy_areas),
       Mapping.new(:world_locations),
       Mapping.new(:people),
       Mapping.new(:roles),
diff --git a/lib/search/registries.rb b/lib/search/registries.rb
index 897e9d3bc..7f8e47cc9 100644
--- a/lib/search/registries.rb
+++ b/lib/search/registries.rb
@@ -8,16 +8,8 @@ def as_hash
       @as_hash ||= {
         organisations:,
         organisation_content_ids: organisations,
-
-        # Whitehall has a thing called `topic`, which is being renamed to "policy
-        # area", because there already are seven things called "topic". Until
-        # Whitehall publishes the policy areas with format "policy_area" rather
-        # than "topic", we will expand `policy_areas` with data from documents
-        # with format `topic`.
-        policy_areas: registry_for_document_format("topic"),
-        document_series: registry_for_document_format("document_series"),
-        document_collections: registry_for_document_format("document_collection"),
-        world_locations: registry_for_document_format("world_location"),
+        document_collections: govuk_registry_for_document_format("document_collection"),
+        world_locations: govuk_registry_for_document_format("world_location"),
         people: govuk_registry_for_document_format("person"),
         roles: govuk_registry_for_document_format("ministerial_role"),
       }
@@ -62,14 +54,6 @@ def govuk_index
       search_server.index_for_search([SearchConfig.govuk_index_name])
     end
 
-    def registry_for_document_format(format)
-      BaseRegistry.new(index, field_definitions, format)
-    end
-
-    def index
-      search_server.index_for_search([SearchConfig.registry_index])
-    end
-
     def field_definitions
       @field_definitions ||= search_server.schema.field_definitions
     end
diff --git a/lib/search_config.rb b/lib/search_config.rb
index 703fb9471..766f66a55 100644
--- a/lib/search_config.rb
+++ b/lib/search_config.rb
@@ -3,7 +3,6 @@ class << self
     attr_writer :instance
 
     %w[
-      registry_index
       metasearch_index_name
       popularity_rank_offset
       auxiliary_index_names
diff --git a/lib/tasks/report_inconsistent_aggregate_values.rake b/lib/tasks/report_inconsistent_aggregate_values.rake
index 2969dfa44..e5288439d 100644
--- a/lib/tasks/report_inconsistent_aggregate_values.rake
+++ b/lib/tasks/report_inconsistent_aggregate_values.rake
@@ -9,10 +9,8 @@ task :report_inconsistent_aggregate_values do
   # Same as in `lib/search/presenters/entity_expander.rb` minus
   # the content_id mappings which are not valid aggregate fields.
   aggregates = %w[
-    document_series
     document_collections
     organisations
-    policy_areas
     world_locations
     people
   ]
diff --git a/spec/unit/result_set_presenter_spec.rb b/spec/unit/result_set_presenter_spec.rb
index 9e7899aa4..6321500ba 100644
--- a/spec/unit/result_set_presenter_spec.rb
+++ b/spec/unit/result_set_presenter_spec.rb
@@ -32,7 +32,7 @@ def sample_docs
        "_source" => {
          "title" => "Dairy farming and schemes",
          "link" => "/dairy-farming-and-schemes",
-         "policy_areas" => %w[farming],
+         "document_collections" => %w[farming],
        },
      }]
   end
@@ -157,9 +157,9 @@ def search_presenter(options)
 
   context "results with a registry" do
     before do
-      policy_area_registry = {
+      document_collections_registry = {
         "farming" => {
-          "link" => "/government/topics/farming",
+          "link" => "/government/collections/farming",
           "title" => "Farming",
         },
       }
@@ -167,11 +167,11 @@ def search_presenter(options)
       @output = described_class.new(
         search_params: Search::QueryParameters.new(
           start: 0,
-          return_fields: %w[policy_areas],
+          return_fields: %w[document_collections],
           aggregate_name: :aggregates,
         ),
         es_response: sample_es_response,
-        registries: { policy_areas: policy_area_registry },
+        registries: { document_collections: document_collections_registry },
       ).present
     end
 
@@ -208,10 +208,10 @@ def search_presenter(options)
     it "have the expanded topic" do
       result = @output[:results][2]
       expect([{
-        "link" => "/government/topics/farming",
+        "link" => "/government/collections/farming",
         "title" => "Farming",
         "slug" => "farming",
-      }]).to eq result["policy_areas"]
+      }]).to eq result["document_collections"]
     end
   end
 end