A Labour MP said she has been threatened with being “gunned down” on the day a top Metropolitan Police officer warned about a “creeping rise” in far-right extremism as a result of Brexit.

Melanie Onn, MP for Great Grimsby, shared on Twitter the message she received from a member of the public, who had given the name Helen.

It read: “‘You are a f****** traitor you silly f****** bitch. We will remember your actions you spineless shit. Watch your back or you will not be forgiven. TRAITOR.'”

The MP said the same person sent a follow-up email including the message: “The likes of you should be f****** gunned down.”

Ms Onn, who came out against a second referendum earlier this week, added: “Everyone in Grimsby knows I’ve never backed down from a debate, even when I’ve had unpopular POV (including in referendum), but we must be allowed to have an opinion without this nonsense.”

Jo Cox, who was Labour MP for Batley and Spen, was killed after being repeatedly shot and stabbed in Birstall in June 2016. Her killer, Thomas Mair, gave his name as “death to traitors, freedom for Britain” at his first court appearance.

Ms Onn’s comments came as Assistant Commissioner of the Metropolitan Police, Neil Basu, expressed his concerns that Brexit could lead to a “creeping rise” in far-right extremism.

Mr Basu said: “What’s most concerning me about Brexit is the potential to divide communities and set communities against each other.”

He told BBC Radio 4’s Today programme: “We have seen some of the behaviour from very, very small groups.

“If you think about what happened outside Parliament just before Christmas and just after Christmas, we had months of very peaceful, very lawful, no problems protest outside Parliament.

“Then a very small group of people managed to turn that atmosphere and that cannot be right. We must make absolutely sure that doesn’t happen.”

A number of cross-party MPs have reported experiencing abuse in recent weeks.

Among them was pro-EU Conservative MP Anna Soubry, who was called a “Nazi” by pro-Brexit protesters as she was interviewed outside Parliament earlier this month.

Nick Boles, MP for Grantham, received a death threat via his website, declaring: “Your days are f****** numbered, traitor. Prepare to die.”

Mr Boles called the sender “inadequate” and added “if [they] knew anything about me he would realise I need no reminding that my days are numbered!”

Labour MP Stephen Doughty has called for “proper action” to be taken against those responsible for abuse outside Parliament, and organised a letter to Met Commissioner, Cressida Dick, signed by 55 MPs and criticising what they called “a lack of co-ordination in the response from the police and appropriate authorities.”