EXCL Len McCluskey and Chris Williamson in public spat amid Labour MP 'open selection' row
Len McCluskey and Chris Williamson had a public bust-up after their feud over changes to the way Labour candidates are selected boiled over.
The Unite general secretary took the controversial MP to task over a Morning Star article in which he accused the union of ignoring its own policy on the issue.
Mr Williamson spent the summer campaigning for a shake-up which would have seen all Labour MPs facing the prospect of selection battles ahead of every general election.
A compromise thrashed out by party bosses kicked out the plan, ensuring trade unions maintain a key role in MP selection.
But deep splits between the unions and Labour's grassroots burst into the open at the party's conference when delegates angrily denounced the move.
In his article, Mr Williamson said: "The rule changes they recommended were endorsed on Sunday after a heated discussion on the conference floor and only after the Unite delegation voted against the union's policy.
"Unite's conference backed mandatory reselection at its 2016 conference. Had the Unite delegation voted in line with their own policy, the outcome would have been very different."
PoliticsHome has learned that Mr McCluskey made clear his anger at Mr Williamson's behaviour when the pair bumped into each other at the Labour conference in Liverpool.
One eyewitness said: "It was a lot of finger-wagging and then Len McCluskey walked off very vigorously. It was a fairly heated argument - Len is quite scary when he's angry."
Unite sources confirmed the altercation had taken place.
One said: "They bumped into each other and Len decided to give Chris a piece of his mind.
"There is anger at him attacking Unite for a rule change that was supported by Jeremy Corbyn's office."
But Mr Williamson told PoliticsHome: "I wouldn't describe it as a clash - we had a conversation, that was all
"I'm going to continue to push for open selections and democratising the Labour."
Asked if he stood by his view that Unite and the other unions had blocked the rule-changes, he said: "You just have to look at the vote. The unions voted one way and the CLPs voted another."