SINN Fein’s seven MPs will fly into London today to take up their Commons offices - sparking Tory fears they may try to wreck the Prime Minister’s wafer thin majority.

The Sun can also reveal the Irish Republican party have refused to rule out taking their seats for the first time to vote through a Labour Queen’s Speech if Jeremy Corbyn offered them a referendum on unifying Ireland.

PA:Press Association 6 Seven Sinn Fein MPs including Barry McElduff (left) and Michelle Gildernew (right) will fly to London to take up their Westminster offices after celebrating with leader Michelle O'Neill (centre)

PA:Press Association 6 The backing of seven Sinn Fein MPs would reduce the Tory majority to just four

The party confirmed that its MPs will travel to Westminster for the House of Commons induction day for newcomers and will sign up for office space, register for staff allowances and expenses - despite their century-long policy of abstention in the UK Parliament.

Their presence at Westminster will spark fears in No10 that they are plotting to break their boycott to join other opposition parties in opposing Theresa May’s Queen’s Speech.

Mr Corbyn has already unveiled his plan to present an alternative Queen’s Speech next week - including pledges to keep the winter fuel allowance, protecting the pensions triple lock and scrapping the bedroom tax, which he hopes will entice enough Tory MPs to deliver a government defeat.

The backing of seven Sinn Fein MPs would reduce the Tory majority to just four - which would bring the Government to the brink of collapse.

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A defeat for Mrs May would topple her premiership and give Mr Corbyn the chance to form a minority Labour government himself.

Labour would have two weeks to get a Queen’s Speech through the Commons and a Sinn Fein insider refused to rule out taking the historic step of taking seats if Republican-supporting Mr Corbyn offered a referendum on Irish unification.

A Sinn Fein insider said: “It’s entirely speculative - we shouldn’t get into the realms of what if, what if, what if.”

Reuters 6 Sinn Fein's president Gerry Adams said a referendum on Irish unity was inevitable

News Group Newspapers Ltd 6 Labour leader Jeremy Corbyn announced he was planning on giving an alternative Queen's speech next week

It came as Sinn Fein president Gerry Adams said a referendum on Irish unity was inevitable as rival parties reconvened in Stormont yesterday to restore power-sharing talks following the six-months deadlock.

He said: “One thing we can say for certainty, there is going to be a referendum on Irish unity,” he said.

“I can’t say when it’s going to be, but there is going to be such a referendum.”

The parties face a deadline of June 29 before direct rule is imposed on Northern Ireland.

Former Irish Taoiseach John Bruton warned Sinn Fein that the prospect of direct rule should scare Irish Republicans given the DUP’s enhanced influence on the UK Government. The unionist party is today set to strike a deal with Mrs May’s government to prop up her minority government.

Getty Images 6 DUP leader Arlene Foster is set to strike a deal with Theresa May to give the Conservatives a majority

Reuters 6 James Brokenshire said he believed a deal to restore power-sharing is possible

Mr Bruton was echoed by DUP leader Arlene Foster, who told Sinn Fein: “If others decide that they are not coming back into the devolved administration here in Northern Ireland then those issues will have to be dealt with at Westminster.

“It is really for Sinn Fein to decide where they want those powers to lie.”

Northern Ireland Secretary James Brokenshire - who flew into Belfast to chair talks yesterday - said he believed a deal to restore power-sharing before the end of the month was possible.

And he insisted the DUP-Tory arrangement in Westminster was an “entirely separate” issue.

Corbyn 'key factor' in talks with Tories

ULSTER unionists have vowed to prop up Theresa May’s enfeebled government for as long as Jeremy Corbyn runs Labour, it was claimed yesterday.

Sources at the DUP said their fierce opposition to the Labour leader – given his IRA sympathies – was a key factor in the talks with the Tories.

Asked how long the "confidence and supply" arrangement could stay in place, the source said: “For as long as Jeremy Corbyn is leader of the Labour Party.”

DUP chief Arlene Foster last month branded Mr Corbyn “abhorrent” in a scathing attack on the leftie for repeatedly refusing to condemn the IRA.

She said: “There were many fine people who reached out to the IRA and asked them to desist. He actually supported them, he wanted them to win!”

DUP MPs were flying to London last night ahead of the reopening of Parliament today.

Labour yesterday attacked the DUP’s “abhorrent” views on gay rights and women’s rights.

But Shadow Trade Secretary Barry Gardiner was forced to admit former Labour PM Gordon Brown held talks about deals with the DUP in the run-up to the 2010 Election – which resulted in a hung parliament.

Tory MPs were yesterday told by the party’s high command to boast about the Conservative record on gay rights.

In a media briefing, Tory MPs were told to make clear the Tories would continue to champion equality.

The briefing revealed by the Guido Fawkes website said: “Conservatives in Government introduced same sex marriage and earlier this year passed ‘Turing’s Law’ to remove historic convictions for consensual acts.

“As we work with others to govern in the national interest and provide the certainty and stability the country needs as we embark on Brexit and beyond – we will continue to promote and champion the equal rights we believe in.”