diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4cfe437..b0d8997 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 9.14.0
+
+* Configure `time_zone` with `govuk_time_zone` [#392](/~https://github.com/alphagov/govuk_app_config/pull/392)
+
 # 9.13.1
 
 * Update dependencies
diff --git a/README.md b/README.md
index 995e2e8..6424ffa 100644
--- a/README.md
+++ b/README.md
@@ -184,7 +184,17 @@ Some frontend apps support languages that are not defined in the i18n gem. This
 
 ## Time zone
 
-This gem sets `config.time_zone` to `"London"` - this cannot currently be overridden in application config.
+This gem sets `config.time_zone` to `"London"` by default.
+
+If you require a different time zone, you can set it with `config.govuk_time_zone`:
+
+```ruby
+config.govuk_time_zone = "UTC"
+```
+
+Note that we've introduced a new config field (`govuk_time_zone`) here, because
+it's otherwise not possible to distinguish between an app using UTC as the
+default and an app explicitly asking for UTC.
 
 ## License
 
diff --git a/lib/govuk_app_config/govuk_timezone.rb b/lib/govuk_app_config/govuk_timezone.rb
index 9d80f08..986f64a 100644
--- a/lib/govuk_app_config/govuk_timezone.rb
+++ b/lib/govuk_app_config/govuk_timezone.rb
@@ -1,14 +1,12 @@
 module GovukTimezone
   def self.configure(config)
-    case config.time_zone
-    when "UTC"
-      Rails.logger.info "govuk_app_config changing time_zone from UTC (the default) to London"
-    when "London"
-      Rails.logger.info "govuk_app_config always sets time_zone to London - there is no need to set config.time_zone in your app"
+    raise "govuk_app_config prevents configuring time_zone with config.time_zone - use config.govuk_time_zone instead" unless config.time_zone == "UTC"
+
+    if config.respond_to?(:govuk_time_zone) && config.govuk_time_zone.present?
+      config.time_zone = config.govuk_time_zone
     else
-      raise "govuk_app_config prevents configuring time_zones other than London - config.time_zone was set to #{config.time_zone}"
+      Rails.logger.info 'govuk_app_config changing time_zone from UTC (the rails default) to London (the GOV.UK default). Set config.govuk_time_zone = "UTC" if you need UTC.'
+      config.time_zone = "London"
     end
-
-    config.time_zone = "London"
   end
 end
diff --git a/lib/govuk_app_config/version.rb b/lib/govuk_app_config/version.rb
index 58a4672..6a90ad9 100644
--- a/lib/govuk_app_config/version.rb
+++ b/lib/govuk_app_config/version.rb
@@ -1,3 +1,3 @@
 module GovukAppConfig
-  VERSION = "9.13.1".freeze
+  VERSION = "9.14.0".freeze
 end
diff --git a/spec/lib/govuk_timezone_spec.rb b/spec/lib/govuk_timezone_spec.rb
index 9c41005..e9df702 100644
--- a/spec/lib/govuk_timezone_spec.rb
+++ b/spec/lib/govuk_timezone_spec.rb
@@ -1,9 +1,10 @@
+require "ostruct"
 require "spec_helper"
 require "govuk_app_config/govuk_timezone"
 
 RSpec.describe GovukError do
   describe ".configure" do
-    let(:config) { Rails::Railtie::Configuration.new }
+    let(:config) { OpenStruct.new }
     let(:logger) { instance_double("ActiveSupport::Logger") }
 
     before do
@@ -17,16 +18,26 @@
       expect(config.time_zone).to eq("London")
     end
 
-    it "should leave time_zones set to London as London" do
-      config.time_zone = "London"
+    it "should allow apps to set time_zone explicitly with config.govuk_time_zone" do
+      config.time_zone = "UTC"
+      config.govuk_time_zone = "Shanghai"
+      GovukTimezone.configure(config)
+      expect(config.time_zone).to eq("Shanghai")
+    end
+
+    it "should default to London if config.govuk_time_zone is nil" do
+      config.time_zone = "UTC"
+      config.govuk_time_zone = nil
       expect(logger).to receive(:info)
       GovukTimezone.configure(config)
       expect(config.time_zone).to eq("London")
     end
 
-    it "should raise an error if configured with any other time zone" do
+    it "should raise an error if config.time_zone is set to anything other than the default UTC" do
+      config.time_zone = "London"
+      expect { GovukTimezone.configure(config) }.to raise_error(/govuk_app_config prevents configuring time_zone with config[.]time_zone/)
       config.time_zone = "Shanghai"
-      expect { GovukTimezone.configure(config) }.to raise_error(/govuk_app_config prevents configuring time_zones/)
+      expect { GovukTimezone.configure(config) }.to raise_error(/govuk_app_config prevents configuring time_zone with config[.]time_zone/)
     end
   end
 end