John Longworth, the former British Chambers of Commerce chief, Annunziata Rees-Mogg (sister of Commons Leader, Jacob Rees-Mogg ), Lance Forman and Lucy Harris are set to quit the Brexit Party and urge people to back the Conservatives at the upcoming election.
The dramatic resignations come with just a week to go before polling day - and just before the Brexit Party leader Nigel Farage records a high-profile interview with the BBC's Andrew Neil.
Unhappiness among the MEPs started to emerge on Wednesday when Longworth, chairperson of the Leave Means Leave group, lost the whip for “disloyalty” to the party and "repeatedly undermining" Mr Farage's election strategy.
Ms Rees-Mogg, MEP for the East Midlands and an ex-Conservative candidate, said: "We need a strong Leave-supporting government to deliver the Brexit 17.4 million voted for. The Conservatives are the only option for Brexit supporters and democrats alike."
The four MEPs who believe voting for Boris Johnson's party at the general election is the way "to ensure Brexit gets delivered" held a press conference in Westminster releasing details of their resignation letter to Farage.
Farage said he was "disappointed" by the MEPs' decision, who will continue to sit as independent MEPs.