Len McCluskey today told MPs opposed to Jeremy Corbyn to “desist” from organising against the Labour leader and said trade unions could mediate between the warring wings of the party.

The General Secretary of Unite, the UK’s largest trade union, labelled last week’s coup attempt as “failed” and warned of the risk of a “civil war” within Labour.

“This has been a political lynching of a decent man – undermined, humiliated, attacked in order to push him out,” McCluskey said.

“Here’s the truth. It has failed. The coup has failed. Jeremy Corbyn is made of stronger stuff. He is a man of steel and he’s made it clear that he will not step down.

“I’m amazed that some of the MPs have fallen into a trap. I think they’ve been seduced by sinister forces in play here.”

McCluskey went on to urge the warring factions of the Labour party too allow trade unions to try to strike a deal to end the conflict.

“I’m calling on Angela Eagle and Owen Smith and anybody else to desist,” he told the Andrew Marr Show.

“We’re professional negotiators. Trust me. We would bring both parties together and resolve this issue.

“The alternative – if Angela goes ahead with this and I hope she doesn’t, or Owen – is we are plunged into a civil war that will be bitter and ugly and may never allow the Labour Party to reunite again. Why would people want to do that?

“Give us a chance. Give the trade unions – who have always been a solid block within our party – bring people together and we will resolve the issues.”

McCluskey also sought to link MPs’ opposition to Corbyn to the work of Portland Communications, a PR firm set up by Tim Allan, who was on the staff at 10 Downing Street under Tony Blair. Portland today said the suggestion of a link was “completely untrue”.

McCluskey is a long-time defender of Corbyn and Unite endorsed the Labour leader during his leadership campaign. Last week the Unite boss, along with leaders of nine other trade unions, demanded Labour MPs recognise Corbyn’s authority, saying that if other MPs wanted him to go, they should trigger a formal leadership contest.