diff --git a/src/IDF/Views/Source.php b/src/IDF/Views/Source.php
index 9ffcec9..dc603e5 100644
--- a/src/IDF/Views/Source.php
+++ b/src/IDF/Views/Source.php
@@ -232,6 +232,25 @@ class IDF_Views_Source
                                                $request);
     }
 
+    public $downloadDiff_precond = array('IDF_Precondition::accessSource');
+    public function downloadDiff($request, $match)
+    {
+        $scm = IDF_Scm::get($request);
+        $commit = $match[2];
+        $branches = $scm->getBranches();
+        if ('commit' != $scm->testHash($commit)) {
+            // Redirect to the first branch
+            $url = Pluf_HTTP_URL_urlForView('IDF_Views_Source::treeBase',
+                                            array($request->project->shortname,
+                                                  $branches[0]));
+            return new Pluf_HTTP_Response_Redirect($url);
+        }
+        $cobject = $scm->getCommit($commit);
+        $rep = new Pluf_HTTP_Response($cobject->changes, 'text/plain');
+        $rep->headers['Content-Disposition'] = 'attachment; filename="'.$commit.'.diff"';
+        return $rep;
+    }
+
     /**
      * Should only be called through self::tree
      */
diff --git a/src/IDF/conf/urls.php b/src/IDF/conf/urls.php
index aaf890d..f08d462 100644
--- a/src/IDF/conf/urls.php
+++ b/src/IDF/conf/urls.php
@@ -171,6 +171,12 @@ $ctl[] = array('regex' => '#^/p/([\-\w]+)/source/commit/([^/]+)/$#',
                'model' => 'IDF_Views_Source',
                'method' => 'commit');
 
+$ctl[] = array('regex' => '#^/p/([\-\w]+)/source/ddiff/([^/]+)/$#',
+               'base' => $base,
+               'priority' => 4,
+               'model' => 'IDF_Views_Source',
+               'method' => 'downloadDiff');
+
 $ctl[] = array('regex' => '#^/p/([\-\w]+)/source/download/([^/]+)/$#',
                'base' => $base,
                'priority' => 4,
diff --git a/src/IDF/templates/idf/source/commit.html b/src/IDF/templates/idf/source/commit.html
index 94b4554..785e6c0 100644
--- a/src/IDF/templates/idf/source/commit.html
+++ b/src/IDF/templates/idf/source/commit.html
@@ -31,6 +31,9 @@
 <h2>{trans 'Change Details'}</h2>
 
 {$diff.as_html()}
+{aurl 'url', 'IDF_Views_Source::downloadDiff', array($project.shortname, $commit)}
+<p class="right soft"><a href="{$url}"><img style="vertical-align: text-bottom;" src="{media '/idf/img/package-grey.png'}" alt="{trans 'Archive'}" align="bottom" /></a> <a href="{$url}">{trans 'Download the diff file'}</a></p>
+
 {/if}
 {/block}
 {block context}