LABOUR’s civil war has intensified after Len McCluskey, the General Secretary of the trade union Unite, accused Tom Watson, the party’s deputy leader, of living in a "world of skulduggery, smears and secret plots".

Mr McCluskey’s attack came just hours after Jeremy Corbyn issued a call for unity and followed a poll that put the Conservatives 19 points ahead.

The continuing internal bickering has led Alex Rowley, Scottish Labour’s deputy leader, to accuse the party’s Westminster group of “ripping itself apart” over Mr Corbyn’s leadership and warned of a voter backlash in May’s local elections.

Mr Rowley, who is in charge of Scottish Labour’s council campaign, said: “We need to get our act together and we need unity.”

The Mid-Fife and Scotland MSP added: “I would appeal for unity. These are senior figures within the Labour Party. They’re letting down everybody out there working hard to get Labour elected. We need unity.”

On Monday, Mr Watson warned of a secret plot between Unite and Momentum, the hard Left campaign group that helped propel Mr Corbyn to the party leadership, to take over the party.

This led to a backlash from some Shadow Cabinet colleagues close to Mr Corbyn with one, John McDonnell, the Shadow Chancellor, publicly berating Mr Watson for what he believed was his attempt to influence the current leadership election in Unite, in which Mr McCluskey is seeking re-election as General Secretary.

In a hard-hitting blog for the Huffington Post website, the union leader said he had been touring the country in recent months meeting "decent" workers, who were worried about their jobs, public services and Brexit and that there existed “another world” in the Labour movement.

"A world of skulduggery, smears and secret plots. That is where you will find Tom Watson. When Labour has needed loyalty, he has been sharpening his knife looking for a back to stab. When unity is required, he manufactures division," wrote Mr McCluskey.

The Unite chief, a former flatmate of Mr Watson’s, said he had been accused of being "secretly in cahoots" with Jon Lansman, the founder of Momentum, to bankroll the grassroots activists’ group.

"That was at breakfast. By lunchtime I was no longer the scheming mastermind but Unite chief of staff Andrew Murray was doing the conspiring instead.

"By evening, he may well have been blaming the Unite caretaker for digging a secret tunnel linking Unite HQ to Jon Lansman's home.

"The fact is that I have never had a private meeting with Lansman about anything in my life, let alone on this alleged scheme," insisted Mr McCluskey.

Only Unite's executive could decide to support such an organisation and there was "no proposal that it should do so," he explained.

The union leader added: "Why the untruth? Watson wants to control the Unite election. He is not ready to leave the matter in the hands of the ordinary working people, who make up our union.

"He has been masterminding a nasty tabloid-style campaign against me; standard fare in political elections, alas, but something new for the trade union movement.

"His transparent plan is to install a puppet, who can take the union back to the bad old days when unions like the one he worked for were in the pockets of employers and failed to put their members' interests first."

On Monday night, Mr Corbyn made a fresh plea for unity and acknowledged that "spirits can run high" because Labour was a "passionate party".

The ballot papers for the Unite contest will be sent out later this week; the result will be announced next month.

Christine Shawcroft, a member of Momentum who sits on Labour’s ruling National Executive Council, said Mr Watson was "rather right-wing" and wanted to return to a "command and control" system for running the party based on a "Blairite model".