Sinn Fein could make the difference in toppling Tory/DUP government say critics.

Sinn Fein is under renewed pressure to take their seats at Westminster after the British Prime Minister Theresa May refused to accept a EU plan which would avoid a return to a physical border between the Republic and Northern Ireland.

Indeed, the London Times reported that David Davis, Britain’s Brexit Minister, upped the stakes dramatically by releasing a statement that Britain will refuse to pay its multi-billion-pound Brexit divorce bill until Brussels backs down on attempts to keep Northern Ireland subject to European Union rules.

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On Wednesday, May rejected an EU document outlining a soft Brexit which she had previously agreed to. The document was also rejected by the DUP who keep May in power.

EU Brexit negotiator to meet with DUP and Sinn Féin next week as unionists reject EU's draft Brexit agreement https://t.co/P2InaLmcdu pic.twitter.com/8LYKEvu2Pd

— BBC News NI (@BBCNewsNI) February 28, 2018

The two parties between them have 326 seats in the 650-seat parliament. With Sinn Fein’s six votes the combined opposition, with some dissident Tories, could defeat the government.

Labour Party leader Jeremy Corbyn has stated he will likely put forward a motion calling for a soft Brexit with no return to a physical Irish border. If it passed it would force an election.

The Government is so divided, the Prime Minister is incapable of delivering a coherent and decisive plan for Brexit. #PMQs pic.twitter.com/VbHOtHJHAQ

— Jeremy Corbyn (@jeremycorbyn) February 28, 2018

May stated she would make her intention plain in a speech on Friday but the Irish government is deeply worried she will announce a hard border option to please her right wingers.

Irish leader Leo Varadkar, lashed out at May saying, “It’s not OK for people, whether pro-Brexit politicians in Britain or parties in Northern Ireland, to just say no now,” Varadkar said. If they did not want the EU’s solution, they must come up with another plan, not just “theoretical stuff”, he told Ireland’s Newstalk radio.

Leo Varadkar urges Sinn Fein to take up seats in Westminster to stop hard Brexit https://t.co/tNW1C5daRF pic.twitter.com/8YhoduqS2B

— i newspaper (@theipaper) February 27, 2018

Varadkar’s deputy, Simon Coveney, said May’s stated intentions – no Irish border controls; no trade barriers between Northern Ireland and the rest of the UK; and leaving the single market and customs union – were “simply not compatible”.

Several political parties have urged Sinn Fein to end abstentionism, in place since 1917 to stop May and the DUP.

In a public challenge to republicans, Varadkar called on Sinn Fein to take its seats in Westminster to “make things better for Ireland.”

His comments were backed by Brendan Howlin, leader of the opposition Labour Party, who said it was time for Sinn Fein to “step up to the plate and defend the interests of the island of Ireland.”

Fianna Fail Brexit spokesman Stephen Donnelly said Sinn Fein’s refusal to take its seats in Westminster “essentially means a hard-line unionist voice is heavily influencing the future of Northern Ireland.”

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British Prime Minister Theresa May.Sky News