There was a fairly well publicised incident in Tower Hamlets (part of London) where a local mayoral election was declared void for reasons including "Voting fraud: ballots were double-cast or cast from false addresses" [1]
The whole Luftur Rahman BS is (I think) more to do with the fact that he's a totally dodgy c&nt (as are quite possibly some of his close associates - juicy 'gossip' in Private Eye), not his ethnic or religious background.
The long line of DodgyC&nts™ at TH has yet to be broken, even going back to "The-Good-Old-Days".
[1] http://www.bbc.co.uk/news/uk-england-london-32428648
Was this guy https://en.wikipedia.org/wiki/Lutfur_Rahman_(politician)#Fal...