The parliamentary arithmetic is tight ahead of crucial votes on the EU withdrawal bill. Government and opposition whips will need to keep track of a number of different groups in order to predict any unexpected upset.

The Tory rebel alliance

Anna Soubry.

The Conservative rebels are close-knit, cemented by attacks from the rightwing press when they defeated the government to win parliament a meaningful vote on the final Brexit deal. The group, which includes Anna Soubry, Dominic Grieve and Sarah Wollaston, has kept its powder dry in recent days, mulling an offer by the government to put the meaningful vote in statute, though the government amendment removes any role for parliament over what happens if a deal is defeated. Rebels may vote for a customs union amendment too, but that is more likely to happen in a forthcoming bill. Ultimately, most in the group are loyal Tories who are unwilling to fatally undermine the prime minister.

The hard Brexiters

The hardline group of pro-Brexit Tories has been disciplined because they are determined to see the EU withdrawal bill pass, even if many of them have been alarmed by some other aspects of the Brexit negotiations in recent days. Jacob Rees-Mogg, who chairs the European Research Group of Eurosceptic Tory MPs, has urged colleagues to get behind the bill and hold fire criticising the prime minister or the negotiations until it has passed.

The Downing Street emissaries

Amber Rudd.

A trio of former cabinet ministers – Amber Rudd, Justine Greening and Damian Green – have been reaching out to Tory colleagues over the past few weeks to urge party unity. Rudd has said the majority of the party want a “sensible Brexit” rather than an extreme on either side. Over the weekend, the former home secretary teamed up with Brexiter ex-cabinet colleague Iain Duncan Smith to write a comment article urging MPs to “demonstrate discipline and unity of purpose in support of the prime minister”. Green told the Mail on Sunday that “the whips can count” and that there was “an overwhelming desire of Conservative MPs to give Theresa the strongest hand at the European council meeting later this month.”

The Tory loyalists

No 10 has expended a lot of energy in recent weeks to try to keep the majority of the parliamentary party onside. Whips have met a number of wavering MPs and the whole parliamentary party was invited in groups to the Department for Exiting the EU to hear briefings on future customs plans. Theresa May addressed the entire party at a private meeting in parliament on Monday night, urging party unity, and the vast majority are likely to fall in line.

Labour remain ultras



Chuka Umunna.

Pro-remain Labour MPs are likely to rebel in significant numbers on a Lords amendment to keep the UK in a Norway-style EEA-arrangement. Many in that group, including former shadow cabinet ministers Chris Leslie, Ben Bradshaw and Chuka Umunna, are furious that the amendment will not be backed by the frontbench, seeing it as a squandered chance to defeat the government. The shadow Brexit secretary, Keir Starmer, has instead put down his own amendment that would commit the government to seek a deal giving the UK access to the EU internal market.

Labour re-leavers

Starmer’s main argument against backing the EEA amendment is the significant number of Labour MPs, many in seats that backed leave, are highly uncomfortable with it. Many MPs who initially backed remain, such as Caroline Flint, Kevan Jones and Jenny Chapman, have repeatedly said that Labour cannot be seen to back a deal that commits the UK to continue being subject to EU rules, including freedom of movement. They, and most of the rest of the parliamentary Labour party, are likely to vote with the Labour whip to abstain on the EEA amendment.

Labour Brexiters

Dennis Skinner.

There is a small but significant number of Labour Brexiters whose votes will be crucial. Leave-supporting MPs such as Graham Stringer and Dennis Skinner were persuaded in December to back the amendment on the parliamentary vote, helping to defeat the government. Labour whips argued that the amendment would not obstruct Brexit and would deliver a damaging blow to the Tories. The success of any amendment will depend on whether those MPs are convinced by that argument again.

The remain rearguard

Both the SNP and Liberal Democrat parties are firmly behind amendments that will deliver a softer Brexit, as are Plaid Cymru and the Green’s Caroline Lucas. Their votes will be crucial to the success of any amendment, but have probably already been taken for granted by the whips counting the numbers on either side.