diff --git a/wagtail/wagtailadmin/static/wagtailadmin/js/blocks/stream.js b/wagtail/wagtailadmin/static/wagtailadmin/js/blocks/stream.js
index 47649e3bd..c030a8780 100644
--- a/wagtail/wagtailadmin/static/wagtailadmin/js/blocks/stream.js
+++ b/wagtail/wagtailadmin/static/wagtailadmin/js/blocks/stream.js
@@ -1,4 +1,26 @@
 (function($) {
+    var StreamBlockMenu = function(opts) {
+        /*
+        Helper object to handle the menu of available block types.
+        Options:
+        childBlocks: list of block definitions (same as passed to StreamBlock)
+        menuItemPrefix: ID prefix of all menu items ('-' + childBlock.name is appended to each one)
+        onChooseBlock: callback fired when a block type is chosen -
+            the corresponding childBlock is passed as a parameter
+        */
+        var self = {};
+
+        /* set up button behaviour */
+        $.each(opts.childBlocks, function(i, childBlock) {
+            var button = $('#' + opts.menuItemPrefix + '-' + childBlock.name);
+            button.click(function() {
+                if (opts.onChooseBlock) opts.onChooseBlock(childBlock);
+            });
+        });
+
+        return self;
+    };
+
     window.StreamBlock = function(opts) {
         /* Fetch the HTML template strings to be used when adding a new block of each type.
         Also reorganise the opts.childBlocks list into a lookup by name
@@ -29,29 +51,27 @@
                         sequenceMember.delete();
                     });
 
-                    /* initialize 'prepend new block' buttons */
-                    function initializeAppendButton(childBlock) {
-                        var template = listMemberTemplates[childBlock.name];
-                        $('#' + sequenceMember.prefix + '-add-' + childBlock.name).click(function() {
+                    /* Set up the 'append a block' menu that appears after the block */
+                    StreamBlockMenu({
+                        'childBlocks': opts.childBlocks,
+                        'menuItemPrefix': sequenceMember.prefix + '-add',
+                        'onChooseBlock': function(childBlock) {
+                            var template = listMemberTemplates[childBlock.name];
                             sequenceMember.appendMember(template);
-                        });
-                    }
-                    for (var i = 0; i < opts.childBlocks.length; i++) {
-                        initializeAppendButton(opts.childBlocks[i]);
-                    }
+                        }
+                    });
                 }
             });
 
-            /* initialize header menu */
-            function initializePrependButton(childBlock) {
-                var template = listMemberTemplates[childBlock.name];
-                $('#' + elementPrefix + '-before-add-' + childBlock.name).click(function() {
+            /* Set up the 'prepend a block' menu that appears above the first block in the sequence */
+            StreamBlockMenu({
+                'childBlocks': opts.childBlocks,
+                'menuItemPrefix': elementPrefix + '-before-add',
+                'onChooseBlock': function(childBlock) {
+                    var template = listMemberTemplates[childBlock.name];
                     sequence.insertMemberAtStart(template);
-                });
-            }
-            for (var i = 0; i < opts.childBlocks.length; i++) {
-                initializePrependButton(opts.childBlocks[i]);
-            }
+                }
+            });
         };
     };
 })(jQuery);