diff --git a/app/__init__.py b/app/__init__.py
index 1c95a7f75..db4a51d31 100644
--- a/app/__init__.py
+++ b/app/__init__.py
@@ -347,24 +347,29 @@ def format_notification_status_as_url(status):
 
 
 def formatted_list(
-  items,
-  conjunction='and',
-  before_each='‘',
-  after_each='’',
-  separator=', ',
-  prefix='',
-  prefix_plural=''
+    items,
+    conjunction='and',
+    before_each='‘',
+    after_each='’',
+    separator=', ',
+    prefix='',
+    prefix_plural=''
 ):
+    if prefix:
+        prefix += ' '
+    if prefix_plural:
+        prefix_plural += ' '
+
     items = list(items)
     if len(items) == 1:
-        return '{prefix} {before_each}{items[0]}{after_each}'.format(**locals())
+        return '{prefix}{before_each}{items[0]}{after_each}'.format(**locals())
     elif items:
         formatted_items = ['{}{}{}'.format(before_each, item, after_each) for item in items]
 
         first_items = separator.join(formatted_items[:-1])
         last_item = formatted_items[-1]
         return (
-            '{prefix_plural} {first_items} {conjunction} {last_item}'
+            '{prefix_plural}{first_items} {conjunction} {last_item}'
         ).format(**locals())
 
 
diff --git a/app/templates/views/check.html b/app/templates/views/check.html
index ef0788923..b8880fe30 100644
--- a/app/templates/views/check.html
+++ b/app/templates/views/check.html
@@ -47,8 +47,8 @@
         </h1>
         <p>
           Your file has {{ recipients.column_headers | formatted_list(
-            prefix='one column, called',
-            prefix_plural='columns called'
+            prefix='one column, called ',
+            prefix_plural='columns called '
           ) }}.
         </p>
         {{ skip_to_file_contents() }}
@@ -65,15 +65,15 @@
         </h1>
         <p>
           Your file has {{ recipients.column_headers | formatted_list(
-            prefix='one column, called',
-            prefix_plural='columns called'
+            prefix='one column, called ',
+            prefix_plural='columns called '
           ) }}.
         </p>
         <p>
           It doesn’t have {{ recipients.column_headers | formatted_list(
             conjunction='or',
-            prefix='a column called',
-            prefix_plural='columns called'
+            prefix='a column called ',
+            prefix_plural='columns called '
           ) }}.
         </p>
         {{ skip_to_file_contents() }}
diff --git a/tests/app/test_jinja_filters.py b/tests/app/test_jinja_filters.py
new file mode 100644
index 000000000..2d24fc00e
--- /dev/null
+++ b/tests/app/test_jinja_filters.py
@@ -0,0 +1,16 @@
+import pytest
+
+from app import formatted_list
+
+
+@pytest.mark.parametrize('items, kwargs, expected_output', [
+    ([1], {}, '‘1’'),
+    ([1, 2], {}, '‘1’ and ‘2’'),
+    ([1, 2, 3], {}, '‘1’, ‘2’ and ‘3’'),
+    ([1, 2, 3], {'prefix': 'foo', 'prefix_plural': 'bar'}, 'bar ‘1’, ‘2’ and ‘3’'),
+    ([1], {'prefix': 'foo', 'prefix_plural': 'bar'}, 'foo ‘1’'),
+    ([1, 2, 3], {'before_each': 'a', 'after_each': 'b'}, 'a1b, a2b and a3b'),
+    ([1, 2, 3], {'conjunction': 'foo'}, '‘1’, ‘2’ foo ‘3’'),
+])
+def test_formatted_list(items, kwargs, expected_output):
+    assert formatted_list(items, **kwargs) == expected_output