Mick Dooley, who had hoped to be elected Ucatt general secretary in a forthcoming election re-run,has been barred from standing, according to the Morning Star newspaper, because he is 'not competent'.
Ucatt is re-running its leadership ballot after the 2009 election was ruled invalid because fewer than 50% of members received ballot papers. Alan Ritchie, who won the most votes at that election, was stripped of office earlier this year as a result.
It is understood that Mr Ritchie has also being prevented from running for office.
Mr Dooley told the Morning Star: "Monty Python could not make it up. Ucatt can now say they have democratically disqualified the two known candidates who have over 150 branch nominations between them, more nominations than the other candidates put together.
"Alan Ritchie has never been found guilty of any offence. I am loathe to admit it, but I find myself sympathetic to his current position. I say why not allow all the candidates state their position on the election address and allow the members to decide. Then get behind the democratically elected candidate and work together to establish a strong union in the construction industry."
Mr Dooley added that he was seeking legal advice.