Tory MP Dominic Grieve has said that the Conservative Party’s grassroots had undergone a “Talibanisation” over Brexit, and claimed that Boris Johnson had “radicalised” over the Irish border issue.

The remarks using language comparing Brexiteers to Islamist terrorists came during a ‘People’s Vote’ event on Tuesday.

During a Conservative Party leadership debate on Monday, frontrunner Boris Johnson said that he would not be willing to accept the EU’s Irish backstop in any withdrawal treaty.

The former attorney-general remarked on the leadership contest that it had been “been played to a tune of growing extremism” and called Mr Johnson’s alleged aversion to resolving the Irish border issue evidence of “radicalisation”.

“When challenged and confronted, he radicalised even further and excluded any possibility of trying to negotiate some way out of the backstop at all. It had to go in its totality,” Mr Grieve said.

Later during a question and answer session with the media, Grieve claimed that there had been a “Talibanisation” of the grassroots Tory associations which prevented Remainers from raising their anti-Brexit positions.

Asked where the pro-Remain MPs are during key votes, Mr Grieve said: “They do exist. They sometimes have concerns about their own local associations and the fear of being deselected. I think there is absolutely no doubt about that.

“There has been a sort of Talibanisation of sections of the Conservative Party grassroots membership, with some vociferous minorities that are often capable of dominating meetings coming along trying to get rid of MPs,” said the Member of Parliament for Beaconsfield, who has himself been subject to attempts at removal by his local Conservative association over his parliamentary efforts to stop Brexit.

Conservative grassroots campaign Stand up 4 Brexit remarked with incredulity: “This is how Grieve describes party members loyal to the Conservative manifesto, who seek to ensure the result of the Referendum is honoured?”

While Leave campaign group Get Britain Out said: “Just in case you didn’t think Project Fear had gone far enough already, Dominic Grieve today compared parts of the Conservative Party membership, who want to deliver Brexit and on the Will of The People, to the Taliban.

“You know the radical Islamic terrorist organisation which has killed hundreds of British soldiers in Afghanistan alongside thousands of civilians. This is simply astounding and outrageous.”

This is not the first time a sitting MP compared Leave supporters to Islamist terrorists. In 2017, Claire Perry said of her fellow Tory MPs who back Brexit: “I feel sometimes I am sitting along with colleagues who are like jihadis in their support for a hard Brexit.”

In April, Labour MP David Lammy compared the Brexit-supporting European Research Group (ERG) to the Nazis, later doubling down on the comments, insisting that the comparison “wasn’t strong enough”.