Chuka Umunna, the MP for Streatham in London and a former leadership contender, said he had reported the threat to police – and said that other Labour colleagues had received the same treatment.
Mr Umunna laid bare the tensions within Labour over Europe, saying he was subjected to a four-letter verbal attack from another Labour MP after breaking the party whip.
In September, he pressed ahead with an amendment to the Queen’s Speech that would have required the government to keep the UK in the European single market. Fifty Labour MPs joined Mr Umunna in defying the party whip on the single market, and three frontbenchers lost their jobs.
Speaking to the Brexit Breakdown podcast from the UK in a Changing Europe research programme, Mr Umunna said critics of Mr Corbyn and pro-EU MPs generally worried about their safety following the murder of MP Jo Cox.
Mr Umunna, who resigned from Mr Corbyn’s shadow cabinet in 2015 over the leader’s euroscepticism, said: “There are a lot of people, I am one of them – I don’t really care about the impact of my decision or my position on Brexit on my future position in the Labour Party. This just comes before everything.”
He added: “It’s a bit bizarre. I’m not naturally a rebel. It’s often quite unpleasant. When I did what I did on the Queen’s Speech, one colleague called me a ‘f***ing w***er’ to my face.
“It put him [Mr Corbyn] in a difficult situation, but frankly, I don’t think I should not do things because it puts someone in a difficult position if it’s a terrible thing for my constituency and the people I represent.
“The echo chamber nature of social media means that I probably don’t see half the stuff I get, but we’ve had death threats.
“I had a death threat which we’ve reported to the police… that was linked to Jeremy. That was one of his supporters.
“It’s quite a regular occurrence it’s not unusual. Loads of colleagues have had it from supporters of Jeremy.”
There was condemnation of a newspaper front page that branded a group of Conservative MPs “Brexit mutineers” for standing against their party on aspects of the EU (Withdrawal) Bill. The front page led to one Scottish Tory, Paul Masterton, receiving hate mail, while other leading pro-EU Conservatives have reported death threats to police.
Mr Umunna said he was persisting with his campaign against Brexit despite his party’s policy of not standing in the way of an exit from the EU because he believes it will harm a future Labour government’s agenda.
“If we do get into government, there is nothing more guaranteed to torpedo our domestic programme than Brexit,” he said.
He suggested that some Labour MPs believe a “hard Brexit”, where the UK crashes out of the EU without a deal, was a price worth paying if the government were to collapse and Mr Corbyn entered 10 Downing Street.
He compared taking a stand to “voting for military action”, saying it was more important for MPs to follow their values rather than the party whip.