Theresa May can still save her Brexit deal – but only if she promises to put it to the people

After nearly three years of stubborn resistance to compromise, the prime minister now says she is in “reaching out” mode. Conservative MPs fumed about the treachery of engaging with the leader of the opposition, whom Theresa May herself frequently frames as a danger to Britain. Since Brexit is a project which inherently endangers jobs and living standards, he was perhaps a natural first port of call.

However, talks between the politburo and Downing Street have now stalled. Jeremy Corbyn seeks some sort of different deal, while May has little room for manoeuvre: the withdrawal agreement, after all, is not open to change. Tweaks to the political declaration are unlikely to be persuasive.

In this stand off, the prime minister is failing to recognise the one issue on which she does have room to move, which is how she attempts to deliver the withdrawal agreement. She has tried and failed three times to deliver it through a sceptical, fractured and fractious House of Commons. Banging her head a fourth time against the wood-panelled walls of the Palace of Westminster is clearly not a sensible option, even if the speaker permitted it.

Yet she could bring forward a fourth “meaningful vote” on a different proposition, which invites MPs to agree the deal, subject to a “confirmatory referendum” – a people’s vote. Some months ago, purists argued that the deal was so dreadful nobody should support it even on this condition. Therein lies permanent deadlock. A pragmatic approach, now, is for those of us who are ardently opposed to Brexit to combine with those who want a deal, to offer the public the final say.

This would be a compromise on the part of those of us who think the deal is radically inferior to the one we have as members of the European Union, and a compromise on the part of those who want the deal delivered. In return for the chance to remain in the EU, ardent pro-Europeans like me and those in my party will give the government the opportunity to put the deal in front of the people.

We have to accept also that an increasing number of people are saying they want no deal, despite the costs. While this is the worst possible way forward, there is now a strong case that the public would consider it a stitch up if it is not one of three options on the ballot paper (no-deal; no Brexit; the government deal). In the event it were chosen, there would have to be a long Article 50 extension for the country to make proper preparations.

There were 280 votes for a referendum in the House of Commons when it was tested on 1 April. Of the 14 Conservatives supporting it, six had voted against the deal the previous Friday. Liberal Democrats (11), The Independent Group (11) and the SNP (34) all opposed the deal en masse, but supported the confirmatory referendum. These 62 additional votes would take May’s deal across the line, on the basis of a referendum with the option to remain. And if Corbyn were to stick to his party’s conference policy of supporting a public vote, the margin could be just as convincing as the one for triggering Article 50 in the first place.

Meaningful Vote 4 – resolved in this way – would give a clear signal to the EU that the United Kingdom has a plan for progress. A Withdrawal Agreement Bill could be brought forward, with a referendum clause, or a Referendum Bill could be brought forward with direct reference to the withdrawal agreement. This sort of detail would need to be thrashed out between the parties.

European elections would proceed, sending British MEPs to defend our interests in the EU institutions, which will continue to have influence over the UK, whether the public choose to stay in the EU (as I hope and expect), or to endorse the withdrawal agreement. These, however, would take place against a much less poisonous background if the present impasse is resolved than if we are still engaged in the same parliamentary jostling on 23 May as we have been in these past six months.

The prime minister is now out of options. Her party has wisely vetoed a hasty general election; the Brexiteers will not support her Brexit deal; and she is not prepared to abandon Brexit altogether. A people’s vote is her last best chance of success, and a chance too for Britain to regain confidence and stature by resuming our rightful place at the European table. Let the battle be joined.

Vince Cable is the leader of the Liberal Democrats and the MP for Twickenham