UKIP chiefs admitted yesterday that they have not found evidence to substantiate Nigel Farage’s allegation that electoral fraud caused a crushing by-election defeat.

Mr Farage claimed he had evidence from “impeccable sources” that “bent” postal votes skewed the result of last week’s Oldham West and Royton by-election.

Despite his predictions that Ukip could make a breakthrough, Ukip candidate John Bickley finished more than 10,000 votes behind Labour victor Jim McMahon.