The numbers look tight

You know it's going to be tight when major party MPs start displaying a detailed knowledge of how Plaid Cymru's three MPs are going to vote (two with the government, one absent, apparently).

The atmosphere in Westminster is fizzing with excitement as the Coalition faces its closest brush yet with outright defeat in a Commons vote.

Labour appears to be pulling out all the stops - John Woodcock, still recovering from falling off a ladder in August, is in. All those on leave, on both sides, have been recalled and the corridors are full of ministers who seldom grace the precincts of the House, unless they are taking questions or leading for the government in debates.

The numbers look tight…

There are now 45 signatures attached to the rebel amendment to the motion on the EU budget. But that total includes five DUP MPs and Labour's Kate Hoey. So 39 Tory rebels…and perhaps a few more who will vote for the amendment, but didn't sign it.

The government will have the support of some minor party MPs, but the SNP, one of their MPs told me, are "very likely" to back the amendment, and most of the eight DUP members have signed it…so, to win, the rebels will need to get something in excess of 45 dissenting Tory MPs through the lobbies in support of their amendment. It may all come down to decisions made by the independent Unionist, Lady Hermon, the Alliance Party's Naomi Long and the Greens' Caroline Lucas.

That assumes that all the potential rebels, declared and otherwise, stick to their guns - and the government whips will be straining every sinew to ensure that they don't. One indicator will be the number of abstentions, and the number of eurosceptic usual suspects among them. Also worth watching will be those MPs who signed other amendments. Jacob Rees-Mogg has a motion down which rejects the mooted EU financial transaction tax and calls on the government to veto anything other than a cut or a freeze in the EU budget. That amendment probably won't be called, but its signatories include a number of MPs whose votes could prove decisive…most notably Liam Fox; but also Caroline Nokes, Andrea Leadsom, Fiona Bruce and Sir Roger Gale. Which way will they jump?

Interestingly, Labour didn't force any kind of test in an earlier euro-vote, today, on Tory backbencher Stewart Jackson's ten minute rule bill on the EU Free Movement of Labour Directive…..that might have served as a bit of a weathervane, but neither the government nor the Labour whips pushed it to a vote.