How Keir Starmer’s new policy could cause Theresa May’s Brexit to unravel

The Labour Party’s new policy on Brexit – set out by Keir Starmer, the Shadow Brexit Secretary, yesterday – has given hope to Remainers. Some of them think it could mean Theresa May losing a vote in the House of Commons, that her plan for Brexit could start to unravel, and that she could be forced to resign.

I won't try and predict what will happen, but I can at least try to set out what some of the possibilities are.

The first question is whether Labour could mobilise a majority of the Commons for its policy. Faced with a choice between Theresa May’s Brexit transition and Keir Starmer’s, it may be that most MPs would prefer Starmer’s. May’s transition phase would be outside the single market, but in a regime as similar to the single market as possible, for a maximum of three years, while Starmer’s would be inside the single market but outside the EU, like Norway, for a maximum of four years.

The hope of many Labour Remainers, of course, is that Labour’s position offers the prospect of permanent single market membership. They hope that the country, possibly led by a Labour government by 2023, might decide not to risk the cliff edge of leaving the single market at all. Some of them, such as Peter Mandelson, writing in the Financial Times today, even see Starmer’s new policy as a stepping stone to putting off leaving the EU altogether – but it is not clear how that works.

The immediate choice is about what kind of temporary arrangement we want after we leave the EU in 2019. Even if a lot of Conservative MPs might support Starmer’s position in theory, would they vote for it in defiance of the Government?

Along with Anna Soubry, Nicky Morgan, Kenneth Clarke and Dominic Grieve, there must be other Tory MPs who feel strongly about the the single market and who feel they have nothing to lose. But there would need to be enough of them to offset the Labour Eurosceptics who would not contemplate staying in the single market, even as a temporary measure. There are nine Labour MPs who supported Leave in the referendum (Ronnie Campbell, John Cryer, Frank Field, Roger Godsiff, Kate Hoey, Kelvin Hopkins, John Mann, Dennis Skinner and Graham Stringer) plus Caroline Flint, who is opposed to single market membership, although she might be persuaded to accept it temporarily. There may be another handful of new MPs or MPs like Flint who think that Leave means Leave.

Given that the DUP is solidly for Brexit, that means Labour needs 15-20 Tory MPs to vote with them to defeat the Government. You could argue that the DUP’s 10 MPs ought to be in favour of staying in the single market, because it would allow them to leave the EU and to keep a soft border between north and south in Ireland. But Sammy Wilson, the DUP’s Brexit spokesperson, made it clear in June that the party supports the Government position, including that on the single market.

The next question is how Labour can engineer a vote that would force the Government to change its negotiating position. There has been speculation at Westminster about an amendment to the Great Repeal Bill, which is now called the EU (Withdrawal) Bill. The debate on the Bill starts next week, and there is expected to be a vote on it on 11 September, although that will be on second reading, which is a preliminary vote on principle of the Bill. The chance to table amendments comes after that.

However, it is not obvious how a defeat on an amendment would change what the Government was seeking in the Brexit talks. It is not even known if the rest of the EU would allow Britain to have Norwegian status for a transitional period – although they probably do want the UK contributions to the EU budget that would go with it. (David Allen Green is interesting on the subject of the complex obfuscation of the EU’s negotiating position.)

In the end, Theresa May could ignore any vote in the Commons, negotiate Brexit on whatever terms she is able to get, and then present MPs with a choice between her deal and no deal at all. After all, MPs have already voted to invoke Article 50, which says the UK leaves the EU come what may in 2019.

She may even be saved by the Fixed-term Parliaments Act, which she promised to repeal in her election manifesto. That is what allows her to be defeated in the Commons on a central question of Government policy without triggering a general election. In 1993 John Major dealt with a Tory rebellion over the Maastricht Treaty by making the vote an issue of “confidence”, meaning that if he lost the vote he would call an election. The Fixed-term Parliaments Act separates confidence votes from votes on policy, so May could lose on the single market and win a separate vote of confidence to carry on as Prime Minister.

It may be, if it becomes clear that Parliament backs the Starmer plan, and if Theresa May refuses to shift, that Conservative MPs would try to replace her with a prime minister who would support it. Philip Hammond, the Chancellor, for example. Even then, there are many obstacles to be overcome. One is that the majority of Tory MPs still support May’s Brexit. Another is that changing the leader opens up a contest to any MP who can secure a nominator and a seconder. Unless all the candidates except one pull out, it would have to go to a vote of all party members, which might give Jacob Rees-Mogg or Andrea Leadsom a chance in a contest that advertised the party’s disarray and division.

As I said, we have learned in the past two years that predictions about politics are a hazardous business.