Backed by Tony Blair, Open Britain has drawn up an ‘attack list’ of 20 Brexit-supporting MPs it will campaign to unseat at the general election, in a bid to sabotage Britain’s exit from the European Union (EU).

The former prime minister said he “fully supports” Open Britain’s plans, which would see constituencies of pro-Brexit figures including Iain Duncan Smith and Kate Hoey flooded with activists who are determined to chain Britain to Brussels.

MPs in the Europhile pressure group’s crosshairs are being targeted for their vocal support for leaving the EU. Other than Labour MP for Vauxhall Ms. Hoey, the hit list consists solely of Tories, featuring figures such as libertarian-leaning Wycombe MP Steve Baker, and former Secretary of State for Northern Ireland Theresa Villiers.

Open Britain believes it can oust the MPs by mobilising the 500,000 supporters on its books, and the group has joined forces with the European Movement and Britain for Europe to access a further 100,000 anti-Brexit activists.

As part of what the pressure group calls its “20/20 key strategy”, the Brussels-loving body, whose board includes New Labour architect Lord Mandelson, is also set to pour resources into defending the seats of 20 MPs from across four parties who are staunchly opposed to Britain’s exit from the EU.

Included in this list is Green MP for Brighton Central, Caroline Lucas, as well as many MPs in Leave-voting constituencies such as Labour’s Mary Creagh, and Norman Lamb and Tom Brake from the Liberal Democrats.

Lord Mandelson, said: “Election candidates of all parties should be demanding that a hard Brexit is rejected and making clear that they will reserve judgment on the outcome until they see whether we get exactly the same trade benefits, as [secretary for Brexit] David Davis has promised.”

The intervention to stop Brexit comes as Blair, an ardent Europhile who opened Britain’s borders to unprecedented mass immigration during his time in office, has urged Labour leader Jeremy Corbyn that the only way the party can win the general election is by pledging to fight Brexit.