A total of 634 votes are in play in today’s debate on the Withdrawal Agreement.

The last time MPs held a Meaningful Vote on the Government’s Brexit deal on March 12 there were 242 in favour, 391 against, with one MP absent.

The magic number for the Government is 318 votes. This would give it a majority – 634 divided by two, plus one.

If everyone who voted in favour on March 12 does so again today, the Government needs to find 76 more votes to reach 318.

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Even if every eligible Conservative MP (311) voted in favour, that would not be enough.

With the DUP already committed to voting against, the Government will need votes from Labour and independent MPs to see them over the line.

There is likely to be a small number of Conservative MPs who will vote against the Withdrawal Agreement today – both from a pro-Brexit and anti-Brexit standpoint.

The exact number is impossible to predict but, for example, if 12 Tories vote against, that would reduce the number of Tories voting in favour to 299, meaning the Government would need 19 extra votes to win.

Four independent MPs and three Labour MPs backed the Government last time and if they do so again, in this scenario the Government would need only another 12 votes to be over the line.

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The final result could be very close.

– The 634 votes in play are the 650 MPs in the House of Commons minus seven Sinn Fein MPs (who do not take their seats), the Speaker and three deputy speakers (who do not vote), one vacancy (the seat of Newport West) and the four tellers – two for, two against – whose votes are not included in the overall result.

If any other MPs are absent from the House of Commons today the number of votes in play will obviously be lower.