A PR worker whose firm union boss Len McCluskey accused of "orchestrating" Labour MPs' "coup" against Jeremy Corbyn has claimed he has received a death threat telling him he will be "coxed" - an apparent reference to Jo Cox.
Labour MPs have lined up to condemn the threat to Kevin McKeever, a partner at Portland Communications and a former parliamentary candidate for the party, as "disgusting", "disgraceful" and "a betrayal of all we stand for".
It comes after Unite general secretary McCluskey accused Portland of being a "sinister" Blairite organisation which has been "critically involved" in Labour MPs' attempts to make Corbyn stand down as leader, in apparent reference to loose allegations made by online blog The Canary.
McKeever has now posted a photo of the alleged death threat on Facebook and Twitter.
It is thought the final sentence is a reference to Jo Cox, the Labour MP who died after being shot and stabbed in Birstall, West Yorkshire, on June 16.
Alongside the picture, McKeever posted a statement, which read: "Many of you will have read posts on a blog suggesting a link between me, my workplace and the moves by Labour MPs in Parliament. They have no basis in truth. I've made my personal views clear on our party's leadership.
"I have, however, been silent for the past few days due to a hand-delivered death threat, suggesting I should be 'coxed', a reference to the murder two weeks ago of Labour MP, Jo Cox.
"On the advice of the police and in the interests of the personal safety of me, my family, I will not be commenting further. We have a Labour Party to return to after this mess. I hope we all reflect."
McCluskey made reference to Portland during a television interview on Sunday. Referring to MPs who want to remove Corbyn, he told BBC One's Andrew Marr Show: "I think they have been seduced by sinister forces in play here.
"Well, if the BBC want to do an investigatory programme of a company called Portland then feel free to do so. This is a PR company with strong links to Tony Blair, right-wing Labour MPs, who have been critically involved in this orchestrated coup."
Labour MPs lined up to condemn the alleged death threat. Corbyn's former leadership rival Liz Kendall tweeted:
A spokesman for hard left group Red Labour condemned the "disgusting threat", adding: "If someone who supports our party or its ideas would ever make threats of this nature, or refer to a murdered comrade in the way used in the letter, then they clearly have no place within our movement.
"All of us at Red Labour unreservedly condemn this horrendous behaviour. We offer solidarity and thoughts with Kevin and his family in this worrying time."
It comes after Corbyn and deputy leader Tom Watson held separate talks with McCluskey in an attempt to resolve the crisis at the top of the Labour Party.