The SDLP has announced it will not stand in three constituencies in Northern Ireland in a bid to facilitate pro-Remain candidates.
The nationalist party will not put forward candidates in North and East Belfast and in North Down as it attempts to prevent DUP Brexiteers winning those seats.
The move in North Belfast will give Sinn Fein candidate John Finucane a better chance of unseating DUP deputy leader and longstanding MP Nigel Dodds, who has a majority of just over 2,000.
The decision not to field a candidate in the north of the city for the first time in the party’s history has prompted claims of hypocrisy from political rivals, given the SDLP’s vocal criticism of Sinn Fein’s Westminster abstentionist policy in other battleground constituencies, such as Foyle.
Former SDLP councillor Mairia Cahill resigned from the party in protest at the move, accusing the party of facilitating a “sectarian headcount”.
The SDLP said it had taken an “extraordinary decision” for an “extraordinary election”.
“We have taken a unilateral decision not to stand candidates in North Down, North Belfast and East Belfast,” said the party.
“Our first priority is to elect pro-Remain MPs to vote against Brexit and Boris Johnson but removing pro-Brexit MPs in Belfast is also critical.”
The Ulster Unionist Party has already stepped aside in North Belfast to give Mr Dodds a better chance of winning.
The UUP decision also proved controversial, as it came only a week after incoming leader Steve Aiken pledged to run in all 18 constituencies in Northern Ireland.
Police are investigating alleged paramilitary threats made to the party in the wake of Mr Aiken’s initial pledge.
The SDLP move in East Belfast is designed to give Alliance Party leader Naomi Long a better chance of defeating incumbent DUP MP Gavin Robinson, while in North Down it is hoping that independent unionist and pro-Remain MP Lady Sylvia Hermon can see off a DUP challenge to unseat her.
The party’s announcement is expected to be met with a reciprocal gesture from Sinn Fein in South Belfast, to strengthen SDLP candidate Claire Hanna’s chance of beating sitting DUP MP Emma Little-Pengelly.