diff --git a/wagtail/wagtailadmin/blocks.py b/wagtail/wagtailadmin/blocks.py
index ea008f1c4..c08533daf 100644
--- a/wagtail/wagtailadmin/blocks.py
+++ b/wagtail/wagtailadmin/blocks.py
@@ -19,6 +19,8 @@ from django.forms.utils import ErrorList
 
 import six
 
+from wagtail.wagtailcore.utils import escape_script
+
 # helpers for Javascript expression formatting
 
 def indent(string, depth=1):
@@ -292,6 +294,11 @@ class CharBlock(FieldBlock):
         # TODO: some kwargs, such as max_length, and *possibly* things like help_text, should be passed to
         # the CharField constructor. Figure out a system for doing this
 
+class RichTextBlock(FieldBlock):
+    def __init__(self, **kwargs):
+        from wagtail.wagtailcore.fields import RichTextArea
+        super(RichTextBlock, self).__init__(CharField(widget=RichTextArea), **kwargs)
+
 # =======
 # Chooser
 # =======
@@ -517,7 +524,7 @@ class ListBlock(Block):
 
         return format_html(
             '<script type="text/template" id="{0}-newmember">{1}</script>',
-            self.definition_prefix, list_member_html
+            self.definition_prefix, mark_safe(escape_script(list_member_html))
         )
 
     def js_initializer(self):
@@ -641,7 +648,7 @@ class BaseStreamBlock(Block):
                 (
                     self.definition_prefix,
                     name,
-                    self.render_list_member(name, child_block.default, '__PREFIX__', '')
+                    mark_safe(escape_script(self.render_list_member(name, child_block.default, '__PREFIX__', '')))
                 )
                 for name, child_block in self.child_blocks.items()
             ]
diff --git a/wagtail/wagtailadmin/static/wagtailadmin/js/blocks/sequence.js b/wagtail/wagtailadmin/static/wagtailadmin/js/blocks/sequence.js
index 2ced19a9f..5e50b44c6 100644
--- a/wagtail/wagtailadmin/static/wagtailadmin/js/blocks/sequence.js
+++ b/wagtail/wagtailadmin/static/wagtailadmin/js/blocks/sequence.js
@@ -69,11 +69,17 @@ For example, they don't assume the presence of a 'delete' button - it's up to th
             newMember._markAdded();
         }
 
+        function elementFromTemplate(template, newPrefix) {
+            /* generate a jquery object ready to be inserted into the list, based on the passed HTML template string.
+            '__PREFIX__' will be substituted with newPrefix, and script tags escaped as <-/script> will be un-escaped */
+            return $(template.replace(/__PREFIX__/g, newPrefix).replace(/<-(-*)\/script>/g, '<$1/script>'));
+        }
+
         self.insertMemberBefore = function(otherMember, template) {
             newMemberPrefix = getNewMemberPrefix();
 
             /* Create the new list member element with the real prefix substituted in */
-            var elem = $(template.replace(/__PREFIX__/g, newMemberPrefix));
+            var elem = elementFromTemplate(template, newMemberPrefix);
             otherMember.container.before(elem);
             var newMember = SequenceMember(self, newMemberPrefix);
             var index = otherMember.getIndex();
@@ -94,7 +100,7 @@ For example, they don't assume the presence of a 'delete' button - it's up to th
             newMemberPrefix = getNewMemberPrefix();
 
             /* Create the new list member element with the real prefix substituted in */
-            var elem = $(template.replace(/__PREFIX__/g, newMemberPrefix));
+            var elem = elementFromTemplate(template, newMemberPrefix);
             otherMember.container.after(elem);
             var newMember = SequenceMember(self, newMemberPrefix);
             var index = otherMember.getIndex() + 1;
@@ -119,7 +125,7 @@ For example, they don't assume the presence of a 'delete' button - it's up to th
             newMemberPrefix = getNewMemberPrefix();
 
             /* Create the new list member element with the real prefix substituted in */
-            var elem = $(template.replace(/__PREFIX__/g, newMemberPrefix));
+            var elem = elementFromTemplate(template, newMemberPrefix);
             list.prepend(elem);
             var newMember = SequenceMember(self, newMemberPrefix);
 
@@ -139,7 +145,7 @@ For example, they don't assume the presence of a 'delete' button - it's up to th
             newMemberPrefix = getNewMemberPrefix();
 
             /* Create the new list member element with the real prefix substituted in */
-            var elem = $(template.replace(/__PREFIX__/g, newMemberPrefix));
+            var elem = elementFromTemplate(template, newMemberPrefix);
             list.append(elem);
             var newMember = SequenceMember(self, newMemberPrefix);
 
diff --git a/wagtail/wagtailadmin/templatetags/wagtailadmin_tags.py b/wagtail/wagtailadmin/templatetags/wagtailadmin_tags.py
index cb049d0e8..650e49f35 100644
--- a/wagtail/wagtailadmin/templatetags/wagtailadmin_tags.py
+++ b/wagtail/wagtailadmin/templatetags/wagtailadmin_tags.py
@@ -1,14 +1,12 @@
 from __future__ import unicode_literals
 
-import re
-
 from django.conf import settings
 from django import template
 from django.contrib.humanize.templatetags.humanize import intcomma
 
 from wagtail.wagtailcore import hooks
 from wagtail.wagtailcore.models import get_navigation_menu_items, UserPagePermissionsProxy, PageViewRestriction
-from wagtail.wagtailcore.utils import camelcase_to_underscore
+from wagtail.wagtailcore.utils import camelcase_to_underscore, escape_script
 from wagtail.wagtailadmin.menu import admin_menu
 
 
@@ -136,7 +134,6 @@ def usage_count_enabled():
 
 class EscapeScriptNode(template.Node):
     TAG_NAME = 'escapescript'
-    SCRIPT_RE = re.compile(r'<(-*)/script>')
 
     def __init__(self, nodelist):
         super(EscapeScriptNode, self).__init__()
@@ -144,8 +141,7 @@ class EscapeScriptNode(template.Node):
 
     def render(self, context):
         out = self.nodelist.render(context)
-        escaped_out = self.SCRIPT_RE.sub(r'<-\1/script>', out)
-        return escaped_out
+        return escape_script(out)
 
     @classmethod
     def handle(cls, parser, token):
diff --git a/wagtail/wagtailcore/utils.py b/wagtail/wagtailcore/utils.py
index 1880684bc..52492e338 100644
--- a/wagtail/wagtailcore/utils.py
+++ b/wagtail/wagtailcore/utils.py
@@ -36,3 +36,13 @@ def resolve_model_string(model_string, default_app=None):
 
     else:
         raise LookupError("Can not resolve {0!r} into a model".format(model_string), model_string)
+
+
+SCRIPT_RE = re.compile(r'<(-*)/script>')
+def escape_script(text):
+    """
+    Escape `</script>` tags in 'text' so that it can be placed within a `<script>` block without
+    accidentally closing it. A '-' character will be inserted for each time it is escaped:
+    `<-/script>`, `<--/script>` etc.
+    """
+    return SCRIPT_RE.sub(r'<-\1/script>', text)