Labour MP Yvette Cooper called the police after a Twitter user who was angry about the Remain campaign threatened to kill her children.

The ex-Cabinet minister, who wants the UK to stay in the EU, posted an image of the sinister threat yesterday evening.

It said: "Hello, Yvette I have received your Stronger In propaganda emails 5 times please stop or I will kill your kids and grandkids."

She tweeted the image, saying: "Got this today for speaking out for Remain..... This has to stop."

It is understood the account was removed after the mother-of-three reported it.

Later, she explained police and Twitter had been alerted, writing: "But this is for all of us. Time to stop the hatred."

The incident comes amid an increase in security for MPs following the death of Ms Cooper's Labour colleague and fellow West Yorkshire MP Jo Cox.

She died after being shot and stabbed in an attack in Birstall near Leeds on Thursday last week.

Speaking publicly for the first time yesterday, her husband Brendan Cox told the BBC his wife had been very worried that the language of politics was "coarsening".

Thomas Mair, 52, has been remanded in custody after being charged with Mrs Cox's murder.

Additional reporting by the Press Association.