Theresa May has been caught out giving different messages to pro and anti-EU Tories – soon she will be forced to take sides

Sooner rather later, the longest fence-sitting exercise in British political history will have to end

Theresa May has been caught out for sending conflicting messages to her party’s pro and anti-EU factions. Sooner rather later, the longest fence-sitting exercise in British political history will have to end, and she will have to take sides.

May’s last-minute personal promise (a bigger role for parliament in the Brexit endgame later this year) to 15 pro-EU potential rebels staved off a humiliating Commons defeat last night. The rebels backed off because they thought they had won her assurance that ministers would need MPs’ approval for their next moves if no deal is reached in the Brexit negotiations by 30 November. Their aim, rightly, is to prevent an economically damaging “no deal” exit next March, and to stop May offering MPs what might be a “lesser of two evils” choice of her deal or no deal.

But when pro-Europeans claimed May’s concession had headed off a “no deal” departure, David Davis, the Brexit secretary, hit the roof, claiming one of his “red lines” had been crossed – that MPs must not conduct the negotiations.

Those who called off their rebellion last night must now stand firm. But Davis is digging in and doesn’t want to make concessions. He issued a menacing statement saying: “We have not, and will not, agree to the House of Commons binding the government’s hands in the negotiations.” One Davis ally added: “The only commitment we have made is to talk.” This called into doubt May’s pledge, fuelling speculation she had hoodwinked the pro-EU Tories.

But the rebels are not crying foul. They think they are on a winning streak. Stephen Hammond, one of their leaders, even heaped praise on the much-criticised chief whip Julian Smith for brokering the deal. “He conducted the negotiations in a sensible and professional manner which enabled us to make progress,” Hammond told me.

The pro-Europeans have the power to hold the prime minister to her promise. The EU (Withdrawal) Bill returns to the House of Lords next Monday, so peers can table an amendment to deliver May’s pledge. That would almost certainly be passed. The bill would then go back to the Commons, when the Tories might need to rebel to nail down May’s commitment.

Her problem is that whenever she makes a concession to the pro-Europeans, hardline Brexiteers throw their toys out of their pram and demand their own sweeties. That’s why Eurosceptics have revived talk of ousting May next month by triggering a vote of confidence in her as Tory leader, though I doubt they would win one.

It is dawning on some Brexiteers that May is not on their side, that the direction of travel is towards a softer Brexit. She keeps putting off the evil day when she takes sides, but might have to as early as next week.

Parliament should force the choice on May. Three MPs (two Labour and one Tory) have told me in the past week they are asking themselves the “what did you do in the war?” question. In other words, what are they doing to halt the devastation, or at least cushion the impact by insisting on a soft Brexit.

Phillip Lee asked himself the question before deciding to resign as justice minister yesterday to join the potential rebels. As he put it: “If, in the future, I am to look my children in the eye and honestly say that I did my best for them I cannot, in all good conscience, support how our country’s exit from the EU looks set to be delivered.”

Labour cannot crow about the Tories’ latest turmoil. Parliament’s growing role in the Brexit debate makes it harder for Jeremy Corbyn to mask his party’s differences. In an attempt to limit divisions, he has ordered his MPs to abstain tonight when the Commons discusses the Lords’ call for the UK to remain in the single market via membership of the European Economic Area (EEA).

Corbyn allies insist that there is no chance of the Lords amendment being passed by MPs. But his critics say Labour is squandering an opportunity to insist on a soft Brexit. Some 16 Tories are ready to back the EEA option when the Commons debates the trade and customs bills next month. So Corbyn could potentially defeat the government if he supported it.

Many MPs feel powerless to stop the devastation. They are frightened of their own shadows, and going against the 2016 referendum, even though that did not specify the form of Brexit. This week’s Commons debates confirm there is a majority there for a soft Brexit; some Tories estimate 200 of their colleagues would back it. MPs have the power to take back control; they must use it before it’s too late.