THE House of Commons will this afternoon quiz the Government over the prospect of a short or long delay to Brexit as Theresa May seeks to win round Northern Ireland’s Democratic Unionists to support her revamped deal.

Justine Greening, the former Education Secretary and a leading supporter of a People's Vote, has successfully tabled an Urgent Question, which a UK minister will respond to.

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MPs will try to find out the likelihood of a third meaningful vote on it taking place in the next 48 hours before the Prime Minister attends the European Council in Brussels on Thursday.

It is thought that crucial to this will be whether or not the DUP can be won over as Tuesday evening’s parliamentary deadline for a decision on a third meaningful vote draws nearer.

Downing St remained tight-lipped on the progress or otherwise of the talks with the DUP at a morning briefing for journalists but made clear a vote would only happen tomorrow or Wednesday if there was a "prospect of success".

The support of the Northern Irish party, whose confidence and supply deal with the Conservatives at Westminster is designed to prop up the Government, is seen as crucial in encouraging Brexiteer Tories to swing behind Mrs May’s plan; although, given the continued opposition from some Conservative MPs, it is increasingly clear even the support of Nigel Dodds’s party might not be enough.

It has been suggested that UK ministers have offered the DUP a “Stormont lock” so that any new regulations imposed on Northern Ireland by the EU would either be adopted by the whole of the UK or could be vetoed by MLAs; if and when the regional assembly returns. There has also been talk of a cut in air passenger duty for Northern Ireland given it is currently lower in the Republic.

It has been further suggested Northern Ireland could be in line for extra money in the forthcoming spending review although Chancellor Philip Hammond at the weekend was keen to stress that his talks with the Northern Irish Unionists had so far not covered extra spending but had focused on regulations.

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No 10’s vagueness continued when the PM’s spokesman confirmed that if Mrs May were not to secure backing for her deal by Wednesday, then the following day she would attend the European Council to ask her fellow EU leaders for a long extension. But, while the Government knew what the length of that requested extension would be, he declined to tell reporters, saying he was “not in a position” to do so. He added: “In terms of next steps progress, we’ll update you as and when we can.”

The Government has until close of play on Tuesday night to table a motion for the following day.

If it does and it wins the meaningful vote, then the PM will seek a “short, technical extension” to enable the necessary legislation to be passed for exit day to take place by mid-April to avoid Britain taking part in the European parliamentary elections.

If it does not table a motion or, if it does and Mrs May loses the vote, then the PM will go to Brussels, seeking a longer extension, which would mean Britain “being required” to take part in the May European parliamentary elections; at an estimated cost to the taxpayer in excess of £100 million.

However, any extension and its length would be in the gift of the EU27.

If the PM does not hold a meaningful vote in the next 48 hours, believing she will not win it, then she is expected to put one before MPs on her revamped deal next week.

The choice facing MPs by then is likely to be accepting Mrs May’s plan or a long extension; the very one Olly Robbins, the PM’s chief Brexit negotiator, mooted in a Brussels bar last month. Asked about this, her spokesman replied: “I’ll pass on that one.”

If either the EU27 declines to offer an extension or if it does and it is rejected by MPs along with Mrs May’s plan, then Britain will leave the EU without a deal on March 29.

Asked if the PM was confident the UK Government was fully prepared for the country to crash out of the EU in 11 days’ time, her spokesman replied: “We stepped up no-deal preparations from December onwards. We have been doing a great deal of preparatory work over the last two years or more. But the PM has always been very clear that in the event of a no-deal, there will be disruption.”

Meanwhile, No 10 made clear that no preparations had been made for the European elections.

Brussels is concerned that if the UK stayed in the EU beyond the May polling date without participating in them, then its lack of MEPs could prove a significant problem to the bloc’s decision-making process.

This is because EU treaties stipulate that all EU citizens have the “right to be represented" and the European Parliament "needs to be properly constituted”.

Also, any future decision the European Parliament made, say, on budgets, could be legally challenged as one member state did not have the necessary representation in it.

At Westminster, MPs have already annulled the European parliamentary elections as part of the Withdrawal Agreement and so would have to legislate to reinstate them if it were decided the UK would take part in them after all.