diff --git a/scrapy/contrib/linkextractors/regex.py b/scrapy/contrib/linkextractors/regex.py
index fc60488c5..cf40b01c2 100644
--- a/scrapy/contrib/linkextractors/regex.py
+++ b/scrapy/contrib/linkextractors/regex.py
@@ -17,8 +17,9 @@ def clean_link(link_text):
 class RegexLinkExtractor(SgmlLinkExtractor):
     """High performant link extractor"""
 
-    def _extract_links(self, response_text, response_url, response_encoding):
-        base_url = urljoin(response_url, self.base_url) if self.base_url else response_url
+    def _extract_links(self, response_text, response_url, response_encoding, base_url=None):
+        if base_url is None:
+            base_url = urljoin(response_url, self.base_url) if self.base_url else response_url
 
         clean_url = lambda u: urljoin(base_url, remove_entities(clean_link(u.decode(response_encoding))))
         clean_text = lambda t: replace_escape_chars(remove_tags(t.decode(response_encoding))).strip()