The man hoping to unseat Len McCluskey as general secretary of Unite has been suspended by the union on the eve of the election.
Gerard Coyne has been suspended as a regional secretary for the West Midlands, pending an investigation.
It has been claimed that Coyne had defamed McCluskey in his campaign literature, during what has become an increasingly bitter election battle between the two union veterans.
Coyne has accused McCluskey of wasting Unite money with his central London flat, while McCluskey has responded in kind by alluding to Coyne's "mansion."
McCluskey is Jeremy Corbyn's most high-profile supporter outside the Labour Party, but Coyne recently told talkRADIO he is far less impressed by Corbyn and may cut off funding to the Labour party if he becomes leader.
Coyne appeared on talkRADIO recently to suggest