diff --git a/django/newforms/forms.py b/django/newforms/forms.py
index 4928065e9d..f47700f857 100644
--- a/django/newforms/forms.py
+++ b/django/newforms/forms.py
@@ -44,7 +44,6 @@ class BaseForm(StrAndUnicode):
         self.data = data or {}
         self.auto_id = auto_id
         self.prefix = prefix
-        self.clean_data = None # Stores the data after clean() has been called.
         self.__errors = None # Stores the errors after clean() has been called.
 
     def __unicode__(self):
@@ -137,11 +136,11 @@ class BaseForm(StrAndUnicode):
         """
         Cleans all of self.data and populates self.__errors and self.clean_data.
         """
-        self.clean_data = {}
         errors = ErrorDict()
         if self.ignore_errors: # Stop further processing.
             self.__errors = errors
             return
+        self.clean_data = {}
         for name, field in self.fields.items():
             # value_from_datadict() gets the data from the dictionary.
             # Each widget type knows how to retrieve its own data, because some
@@ -160,7 +159,7 @@ class BaseForm(StrAndUnicode):
         except ValidationError, e:
             errors[NON_FIELD_ERRORS] = e.messages
         if errors:
-            self.clean_data = None
+            delattr(self, 'clean_data')
         self.__errors = errors
 
     def clean(self):
diff --git a/tests/regressiontests/forms/tests.py b/tests/regressiontests/forms/tests.py
index 0852fbcf0e..6e2f898645 100644
--- a/tests/regressiontests/forms/tests.py
+++ b/tests/regressiontests/forms/tests.py
@@ -1544,6 +1544,10 @@ Empty dictionaries are valid, too.
 {'first_name': [u'This field is required.'], 'last_name': [u'This field is required.'], 'birthday': [u'This field is required.']}
 >>> p.is_valid()
 False
+>>> p.clean_data
+Traceback (most recent call last):
+...
+AttributeError: 'birthday' object has no attribute 'clean_data'
 >>> print p
 <tr><th><label for="id_first_name">First name:</label></th><td><ul class="errorlist"><li>This field is required.</li></ul><input type="text" name="first_name" id="id_first_name" /></td></tr>
 <tr><th><label for="id_last_name">Last name:</label></th><td><ul class="errorlist"><li>This field is required.</li></ul><input type="text" name="last_name" id="id_last_name" /></td></tr>
@@ -1572,6 +1576,10 @@ Form.is_valid() will return False.
 {}
 >>> p.is_valid()
 False
+>>> p.clean_data
+Traceback (most recent call last):
+...
+AttributeError: 'birthday' object has no attribute 'clean_data'
 >>> print p
 <tr><th><label for="id_first_name">First name:</label></th><td><input type="text" name="first_name" id="id_first_name" /></td></tr>
 <tr><th><label for="id_last_name">Last name:</label></th><td><input type="text" name="last_name" id="id_last_name" /></td></tr>
@@ -1611,8 +1619,9 @@ u'<ul class="errorlist"><li>first_name<ul class="errorlist"><li>This field is re
 * birthday
   * This field is required.
 >>> p.clean_data
->>> repr(p.clean_data)
-'None'
+Traceback (most recent call last):
+...
+AttributeError: 'birthday' object has no attribute 'clean_data'
 >>> p['first_name'].errors
 [u'This field is required.']
 >>> p['first_name'].errors.as_ul()