diff --git a/Gemfile.lock b/Gemfile.lock
index b9a11901cc..0266a41ab5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -9,8 +9,6 @@ PATH
       rails (>= 5.0.0.1)
       rake
       rouge
-      sass (= 3.7.4)
-      sassc-rails (>= 2.0.1)
       sprockets (< 4)
 
 GEM
@@ -61,9 +59,9 @@ GEM
       public_suffix (>= 2.0.2, < 5.0)
     arel (9.0.0)
     ast (2.4.0)
-    brakeman (4.8.0)
+    brakeman (4.8.1)
     builder (3.2.4)
-    byebug (11.1.1)
+    byebug (11.1.3)
     capybara (3.32.1)
       addressable
       mini_mime (>= 0.1.3)
@@ -134,7 +132,7 @@ GEM
       activesupport (>= 4.0)
       logstash-event (~> 1.2.0)
       request_store
-    loofah (2.4.0)
+    loofah (2.5.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.1)
@@ -144,7 +142,7 @@ GEM
     method_source (1.0.0)
     mime-types (3.3.1)
       mime-types-data (~> 3.2015)
-    mime-types-data (3.2019.1009)
+    mime-types-data (3.2020.0425)
     mimemagic (0.3.4)
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
@@ -160,7 +158,7 @@ GEM
       ast (~> 2.4.0)
     phantomjs (2.1.1.0)
     plek (3.0.0)
-    pry (0.13.0)
+    pry (0.13.1)
       coderay (~> 1.1)
       method_source (~> 1.0)
     pry-byebug (3.9.0)
@@ -201,9 +199,6 @@ GEM
     rainbow (3.0.0)
     raindrops (0.19.1)
     rake (13.0.1)
-    rb-fsevent (0.10.3)
-    rb-inotify (0.10.1)
-      ffi (~> 1.0)
     regexp_parser (1.7.0)
     request_store (1.5.0)
       rack (>= 1.4)
@@ -255,12 +250,7 @@ GEM
     ruby-progressbar (1.10.1)
     rubyzip (2.3.0)
     safe_yaml (1.0.5)
-    sass (3.7.4)
-      sass-listen (~> 4.0.0)
-    sass-listen (4.0.0)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
-    sassc (2.2.1)
+    sassc (2.3.0)
       ffi (~> 1.9)
     sassc-rails (2.1.2)
       railties (>= 4.0.0)
@@ -292,10 +282,10 @@ GEM
       unf_ext
     unf_ext (0.0.7.7)
     unicode-display_width (1.7.0)
-    unicorn (5.5.4)
+    unicorn (5.5.5)
       kgio (~> 2.6)
       raindrops (~> 0.7)
-    webdrivers (4.2.0)
+    webdrivers (4.3.0)
       nokogiri (~> 1.6)
       rubyzip (>= 1.3.0)
       selenium-webdriver (>= 3.0, < 4.0)
@@ -324,6 +314,7 @@ DEPENDENCIES
   pry-byebug
   rspec-rails (~> 4.0)
   rubocop-govuk (~> 3)
+  sassc-rails (~> 2)
   selenium-webdriver (= 3.142.7)
   uglifier (>= 4.1.0)
   webmock (~> 3.8.3)
diff --git a/govuk_publishing_components.gemspec b/govuk_publishing_components.gemspec
index db5bcba7f9..7b018d7b02 100644
--- a/govuk_publishing_components.gemspec
+++ b/govuk_publishing_components.gemspec
@@ -22,8 +22,6 @@ Gem::Specification.new do |s|
   s.add_dependency "rails", ">= 5.0.0.1"
   s.add_dependency "rake"
   s.add_dependency "rouge"
-  s.add_dependency "sass", "3.7.4"
-  s.add_dependency "sassc-rails", ">= 2.0.1"
   s.add_dependency "sprockets", "< 4"
 
   s.add_development_dependency "capybara", "~> 3.25"
@@ -35,6 +33,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency "pry-byebug"
   s.add_development_dependency "rspec-rails", "~> 4.0"
   s.add_development_dependency "rubocop-govuk", "~> 3"
+  s.add_development_dependency "sassc-rails", "~> 2"
   s.add_development_dependency "selenium-webdriver", "= 3.142.7"
   s.add_development_dependency "uglifier", ">= 4.1.0"
   # Webmock is needed to load slimmer test helpers