diff --git a/.env.example b/.env.example
index f670cc990..d5921a766 100644
--- a/.env.example
+++ b/.env.example
@@ -12,4 +12,5 @@ MAX_AGE: 90
 PASS_THRESHOLD: 2
 BLOCK_THRESHOLD: -1
 PROJECT_URL: https://openpolitics.org.uk/manifesto
-PROJECT_NAME: The OpenPolitics Manifesto
\ No newline at end of file
+PROJECT_NAME: The OpenPolitics Manifesto
+CLA_URL: https://openpolitics.org.uk/manifesto/cla.html
\ No newline at end of file
diff --git a/app/controllers/edit_controller.rb b/app/controllers/edit_controller.rb
index 25549966f..a19d4fb67 100644
--- a/app/controllers/edit_controller.rb
+++ b/app/controllers/edit_controller.rb
@@ -48,10 +48,8 @@ def commit
     # open PR
     pull_from = forked ? "#{@current_user.login}:#{new_branch}" : branch_name
     @pr = open_pr(pull_from, @branch, @summary, @description)
-    # Check for CLA
-    @cla_url = "#{ENV.fetch("SITE_URL")}/cla.html"
-    r = Faraday.get @cla_url
-    @has_cla = (r.status == 200)
+    # Does the proposer need to sign a CLA?
+    @proposer_needs_to_sign_cla = current_user.try(:needs_to_sign_cla?)
   end
 
   private
diff --git a/app/controllers/proposals_controller.rb b/app/controllers/proposals_controller.rb
index 95d8df793..3c3f8b856 100644
--- a/app/controllers/proposals_controller.rb
+++ b/app/controllers/proposals_controller.rb
@@ -20,6 +20,8 @@ def show
     # Get activity list
     presenter = ProposalPresenter.new(@proposal)
     @activity = presenter.activity_log
+    # Does the proposer need to sign a CLA?
+    @proposer_needs_to_sign_cla = current_user.try(:needs_to_sign_cla?) && @is_author
   end
 
   def webhook
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index 4a019ae82..27b6a5eb2 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -26,10 +26,16 @@ def show
   end
 
   def edit
+    @has_cla = ENV["CLA_URL"].present?
   end
 
   def update
-    @user.update!(user_params)
+    if params.has_key?(:cla_accepted)
+      accept_cla
+    else
+      @user.update!(user_params)
+    end
+
     redirect_to edit_user_path(@user)
   end
 
@@ -48,4 +54,12 @@ def authorise
   def user_params
     params.require(:user).permit(:email, :notify_new)
   end
+
+  def accept_cla
+    @user.update!(cla_accepted: true)
+
+    @user.proposed.each do |pr|
+      UpdateProposalJob.perform_later pr.number
+    end
+  end
 end
diff --git a/app/models/concerns/github_pull_request.rb b/app/models/concerns/github_pull_request.rb
index 904059ffc..2e234cd34 100644
--- a/app/models/concerns/github_pull_request.rb
+++ b/app/models/concerns/github_pull_request.rb
@@ -63,6 +63,17 @@ def set_time_build_status
     end
   end
 
+  def set_cla_build_status
+    status = "groupthink/cla"
+    if has_cla?
+      if proposer_needs_to_sign_cla?
+        set_build_status(:pending, I18n.t("build_status.cla.pending"), status)
+      else
+        set_build_status(:success, I18n.t("build_status.cla.accepted"), status)
+      end
+    end
+  end
+
   def merge_pr!
     Octokit.merge_pull_request(ENV.fetch("GITHUB_REPO"), number)
     true
diff --git a/app/models/concerns/user_admin.rb b/app/models/concerns/user_admin.rb
index 7ce3f0a52..f79efc146 100644
--- a/app/models/concerns/user_admin.rb
+++ b/app/models/concerns/user_admin.rb
@@ -21,6 +21,7 @@ module UserAdmin
         field :role
         field :author
         field :voter
+        field :cla_accepted
       end
     end
   end
diff --git a/app/models/concerns/votable.rb b/app/models/concerns/votable.rb
index 6b964a558..4688882fb 100644
--- a/app/models/concerns/votable.rb
+++ b/app/models/concerns/votable.rb
@@ -43,6 +43,7 @@ def count_votes!
     unless closed?
       set_vote_build_status
       set_time_build_status
+      set_cla_build_status
     end
   end
 
diff --git a/app/models/proposal.rb b/app/models/proposal.rb
index cb18134c3..fa9f4788e 100644
--- a/app/models/proposal.rb
+++ b/app/models/proposal.rb
@@ -52,6 +52,14 @@ def too_new?
     age < Rules.min_age
   end
 
+  def has_cla?
+    ENV["CLA_URL"].present?
+  end
+
+  def proposer_needs_to_sign_cla?
+    proposer.try(:needs_to_sign_cla?)
+  end
+
   def update_state!
     state = pr_closed? ? closed_state : open_state
     update!(state: state)
@@ -90,7 +98,7 @@ def closed_state
     def open_state
       return nil if pr_closed?
       return "dead" if too_old?
-      return "blocked" if blocked?
+      return "blocked" if blocked? || proposer_needs_to_sign_cla?
       if passed?
         return too_new? ? "agreed" : "passed"
       end
diff --git a/app/models/user.rb b/app/models/user.rb
index 78584f802..29ba677ae 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -95,4 +95,8 @@ def vote(proposal)
   def to_param
     login
   end
+
+  def needs_to_sign_cla?
+    ENV["CLA_URL"].present? && !cla_accepted
+  end
 end
diff --git a/app/views/edit/commit.html.erb b/app/views/edit/commit.html.erb
index 825c6eedb..08cf1fde5 100644
--- a/app/views/edit/commit.html.erb
+++ b/app/views/edit/commit.html.erb
@@ -1,24 +1,20 @@
-<div class="alert alert-success">
+<div class="form-group alert alert-success">
   <%= fa_icon 'check-circle' %>
   <%= t 'help.success_title' %>
 </div>
 
-<div>
+<div class="form-group">
   <p>
     <%= t 'help.success' %>
   </p>
-  <% if @has_cla %>
-    <p>
-      <%= t :cla %>
-    </p>
-    <p>
-      <%= link_to "#{t(:view_cla)}".html_safe, @cla_url, class: 'btn btn-primary' %>
-    </p>
-  <% end %>
 </div>
 
-<div>
+<div class="form-group">
   <%= link_to "#{fa_icon('globe')} #{t(:return)}".html_safe, @return_to, class: 'btn btn-primary' if @return_to %>
   <%= link_to "#{fa_icon('code-fork')} #{t(:view)}".html_safe, proposal_path(@pr), class: 'btn btn-default' %>
   <%= link_to "#{fa_icon('list')} #{t(:view_all)}".html_safe, proposals_path, class: 'btn btn-default' %>
 </div>
+
+<% if @proposer_needs_to_sign_cla %>
+  <%= render partial: 'shared/cla_warning', locals: { user: current_user } %>
+<% end %>
diff --git a/app/views/proposals/show.html.erb b/app/views/proposals/show.html.erb
index 7f016a45e..3402c5939 100644
--- a/app/views/proposals/show.html.erb
+++ b/app/views/proposals/show.html.erb
@@ -38,6 +38,12 @@
   </div>
 </div>
 
+<% if @proposer_needs_to_sign_cla %>
+  <div class='row'>
+    <%= render partial: 'shared/cla_warning', locals: { user: @proposal.proposer } %>
+  </div>
+<% end %>
+
 <hr/>
 
 <div class='row'>
diff --git a/app/views/shared/_cla_warning.html.erb b/app/views/shared/_cla_warning.html.erb
new file mode 100644
index 000000000..7e8b0ef08
--- /dev/null
+++ b/app/views/shared/_cla_warning.html.erb
@@ -0,0 +1,17 @@
+<div class="form-group alert alert-warning">
+  <%= fa_icon 'exclamation-circle' %>
+  <%= t 'cla_title' %>
+</div>
+
+<div class="form-group">
+  <p>
+    <%= t 'cla' %>
+  </p>
+  <p>
+    Please <%= link_to 'edit your profile', edit_user_path(user) %> and accept <a href='<%= ENV.fetch("CLA_URL")%>' target='_blank' rel='noopener noreferrer'>the license agreement</a> to unblock your proposal.
+  </p>
+</div>
+
+<div class="form-group">
+  <%= link_to "#{fa_icon('cog lg')} #{t(:edit_profile)}".html_safe, edit_user_path(user), class: 'btn btn-primary' %>
+</div>
diff --git a/app/views/users/edit.html.erb b/app/views/users/edit.html.erb
index 65bd66d3a..51751a31a 100644
--- a/app/views/users/edit.html.erb
+++ b/app/views/users/edit.html.erb
@@ -28,3 +28,32 @@
     </div>
   </div>
 <% end %>
+
+<% if @has_cla %>
+  <h2>Contributor License Agreement</h2>
+
+  <p>
+    <%= t :cla %>
+  </p>
+
+  <% if @user.needs_to_sign_cla? %>
+    <%= form_for @user, html: {class: "form-horizontal", style: 'clear: right'} do |f| %>
+      <%= hidden_field_tag "cla_accepted", true %>
+
+      <div class="form-group">
+        <div class="col-sm-offset-2 col-sm-10">
+          <%= link_to "#{t(:view_cla)}".html_safe, ENV.fetch("CLA_URL"), class: 'btn btn-default', target: :_blank, rel: 'noopener noreferrer' %>
+          <%= f.submit class: "btn btn-primary", value: t(:sign_cla) %>
+        </div>
+      </div>
+    <% end %>
+  <% else %>
+    <div class="col-sm-offset-2 col-sm-10">
+      <%= fa_icon 'check' %>
+      You have signed the <a href='<%= ENV.fetch("CLA_URL")%>' target='_blank' rel='noopener noreferrer'>contributor license agreement</a>.
+    </div>
+  <% end %>
+
+  <span style="clear: both">&nbsp;</span>
+
+<% end %>
diff --git a/config/locales/en.yml b/config/locales/en.yml
index f3d869e9d..428915be5 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -27,9 +27,12 @@ en:
   return: Return to site
   view: View your proposal
   view_all: View all proposals
+  edit_profile: Edit profile
   signed_out_site_intro: To contribute you need to log in with a free GitHub account. GitHub is a popular code-sharing site which hosts the site content.
   signed_in_site_intro: There is no way at the moment to explore github content here. Please go to the project you want to edit on GitHub and follow a link to the editor. Thanks!
-  cla: This project has a CLA (Contributor License Agreement). You may need to agree to it before your change can be accepted, if you haven't already.
+  cla_title: Your proposal is blocked until you accept the contributor license agreement.
+  cla: This manifesto has a Contributor License Agreement (CLA) which you must accept before any of your proposals can be included.
+  sign_cla: Accept CLA
   view_cla: View CLA
   help:
     edit: Make your changes in the editor below, then hit "Submit changes" at the bottom.
@@ -70,4 +73,7 @@ en:
     time:
       too_old: "The change has been open for more than %{max_age} days, and should be closed (age: %{age}d)."
       too_new: "The change has not yet been open for %{min_age} days (age: %{age}d)."
-      success: "The change has been open long enough to be merged (age: %{age}d)."
\ No newline at end of file
+      success: "The change has been open long enough to be merged (age: %{age}d)."
+    cla:
+      pending: The contributor license agreement has not been accepted.
+      accepted: The contributor license agreement has been accepted.
\ No newline at end of file
diff --git a/spec/models/proposal_spec.rb b/spec/models/proposal_spec.rb
index 2c87ffca4..86782d647 100644
--- a/spec/models/proposal_spec.rb
+++ b/spec/models/proposal_spec.rb
@@ -3,7 +3,7 @@
 require "rails_helper"
 
 RSpec.describe Proposal, type: :model do
-  context "when checking overall state" do
+  context "when checking overall state without a CLA" do
     let(:pr) { create :proposal }
 
     context "when the upstream PR has been closed" do
@@ -34,6 +34,7 @@
           BLOCK_THRESHOLD: "-1",
           MIN_AGE: "7",
           MAX_AGE: "90",
+          CLA_URL: nil,
         }
         ClimateControl.modify env do
           example.run
@@ -76,6 +77,120 @@
     end
   end
 
+  context "when checking overall state with a signed CLA" do
+    let(:proposer) { create :user, cla_accepted: true }
+    let(:pr) { create :proposal, proposer: proposer }
+
+    context "when the upstream PR is still open" do
+      around do |example|
+        env = {
+          YES_WEIGHT: "1",
+          NO_WEIGHT: "-1",
+          BLOCK_WEIGHT: "-1000",
+          PASS_THRESHOLD: "2",
+          BLOCK_THRESHOLD: "-1",
+          MIN_AGE: "7",
+          MAX_AGE: "90",
+          CLA_URL: "https://example.org/cla.html",
+        }
+        ClimateControl.modify env do
+          example.run
+        end
+      end
+
+      before do
+        allow(pr).to receive(:pr_closed?).and_return(false)
+      end
+
+      it "stores old pull requests as dead" do
+        allow(pr).to receive_messages(age: 100)
+        pr.update_state!
+        expect(pr.state).to eq "dead"
+      end
+
+      it "stores blocked pull requests as blocked" do
+        allow(pr).to receive_messages(score: -500, age: 10)
+        pr.update_state!
+        expect(pr.state).to eq "blocked"
+      end
+
+      it "stores PRs with enough votes and enough time as passed" do
+        allow(pr).to receive_messages(score: 5, age: 10)
+        pr.update_state!
+        expect(pr.state).to eq "passed"
+      end
+
+      it "stores PRs with enough votes and not enough time as agreed" do
+        allow(pr).to receive_messages(score: 5, age: 5)
+        pr.update_state!
+        expect(pr.state).to eq "agreed"
+      end
+
+      it "stores PRs with not enough votes and not enough time as pending" do
+        allow(pr).to receive_messages(score: 1, age: 5)
+        pr.update_state!
+        expect(pr.state).to eq "waiting"
+      end
+    end
+  end
+
+  context "when checking overall state with an unsigned CLA" do
+    let(:proposer) { create :user, cla_accepted: false }
+    let(:pr) { create :proposal, proposer: proposer }
+
+    context "when the upstream PR is still open" do
+      around do |example|
+        env = {
+          YES_WEIGHT: "1",
+          NO_WEIGHT: "-1",
+          BLOCK_WEIGHT: "-1000",
+          PASS_THRESHOLD: "2",
+          BLOCK_THRESHOLD: "-1",
+          MIN_AGE: "7",
+          MAX_AGE: "90",
+          CLA_URL: "https://example.org/cla.html",
+        }
+        ClimateControl.modify env do
+          example.run
+        end
+      end
+
+      before do
+        allow(pr).to receive(:pr_closed?).and_return(false)
+      end
+
+      it "stores old pull requests as dead" do
+        allow(pr).to receive_messages(age: 100)
+        pr.update_state!
+        expect(pr.state).to eq "dead"
+      end
+
+      it "stores blocked pull requests as blocked" do
+        allow(pr).to receive_messages(score: -500, age: 10)
+        pr.update_state!
+        expect(pr.state).to eq "blocked"
+      end
+
+      it "stores PRs with enough votes and enough time as passed" do
+        allow(pr).to receive_messages(score: 5, age: 10)
+        pr.update_state!
+        expect(pr.state).to eq "blocked"
+      end
+
+      it "stores PRs with enough votes and not enough time as agreed" do
+        allow(pr).to receive_messages(score: 5, age: 5)
+        pr.update_state!
+        expect(pr.state).to eq "blocked"
+      end
+
+      it "stores PRs with not enough votes and not enough time as pending" do
+        allow(pr).to receive_messages(score: 1, age: 5)
+        pr.update_state!
+        expect(pr.state).to eq "blocked"
+      end
+    end
+  end
+
   context "with notification of new proposals" do
     let!(:proposer) { create :user, voter: true, notify_new: true }
     let!(:voter) { create :user, voter: true, notify_new: true }