Chancellor Philip Hammond and Home Secretary Amber Rudd are facing deselection threats from a Brexit campaign group.
Leave.EU said it plans to send letters to every voter who lives in the pair’s constituencies advising how and why they should campaign for their removal.
The group said it will not lead the process but wants to give it the “first shove” in the hope Brexiteers will join the Conservative Party branches in the constituencies of Mr Hammond and Ms Rudd, and ultimately seek to table a no confidence motion.
Leave.EU is targeting the two Cabinet ministers as it believes they have sought to “meddle” in the Brexit process.
Former Ukip donor Arron Banks, in the letter intended for Mr Hammond’s Runnymede and Weybridge constituents, accuses the Chancellor of proposing a “lengthy and unnecessary” transition period of up to three years from March 2019.
The Leave.EU chairman wrote: “This would mean that free movement and financial contributions would continue until at least April 2022.
“He is part of a cabal of Westminster MPs who believe that if they can delay exit, they can overturn the wishes of the 52% who despite threats from the political classes drew upon the courage of their conviction at the ballot box.”
Ms Rudd, considered a potential Tory leadership contender in any contest to succeed Theresa May, held her Hastings and Rye seat at this year’s general election with a majority of 346.