Indeed. YouGov's president, Peter Kellner, a friend of Tony Blair, is married to Baroness Cathy Ashton. The highest paid female politician around(even paid more than Obama) and who has never been elected to anything in her life. Blair made her a Baroness so she could get into the Lords to get the Lisbon Treaty through, which she did.
Still, I don't think YouGov would fabricate figures as high as a 20 point difference. Perhaps they merely doubled a 10 point lead.