The Government’s broken promises on Brexit have finally come home to roost. It promised trade talks in parallel with the divorce talks. Instead Theresa May agreed to fork out £39 billion with no treaty in return. Michael Gove promised “the day after we vote to leave, we hold all the cards and we can choose the path we want”. But that hasn’t been the case. It promised high-tech customs solutions at the Irish border and new trade deals. And it promised a December vote on the deal, but broke that one too.

Like Nick Clegg promising not to raise tuition fees and then tripling them, the Prime Minister has learned that saying one thing but doing another comes at a cost — in this case more than a third of her own MPs voting against her flagship policy. Party leaders are rarely forgiven for putting short-term political interests above those of the country.

So what happens next? If Jeremy Corbyn’s attempt to trigger a general election isn’t successful , then next week we will have another Commons motion on the Government’s Plan B. That motion will be amendable. And with Parliament at an impasse, the case for a People’s Vote will be overwhelming.

All the attention will be on the pledge made at Labour Party conference in September: if a general election cannot be achieved and if the Government’s proposal is defeated then the outstanding option is for Labour to campaign for a People’s Vote.

Polling shows a majority in every Labour constituency for a new Brexit vote — 86 per cent of Labour members say they want a public vote. Most Labour MPs agree too. Asking the people what they think is an option that can’t be ducked any longer.

Most people — especially the two million young people who didn’t get a chance to vote in the referendum nearly three years ago — now expect Labour to deliver on this promise.

If Labour MPs are whipped to support a final say for the public, combined with the now growing number of Conservative MPs supporting a People’s Vote, a majority is achievable.

This is therefore one of those unusual moments when the future of the country is in the hands of the Leader of the Opposition. So will Jeremy Corbyn keep that Labour promise or break it? The hundreds of thousands who marched through London last year in support of a People’s Vote will feel cheated if Labour’s front bench back out of it.

If Jeremy Corbyn breaches the trust placed in him by those who want a People’s Vote, then he risks following the path of Nick Clegg nearly a decade ago. A broken promise on a People’s Vote could devastate Labour’s fortunes in the same way it did for Clegg after the tuition fees betrayal. It would be a monumental mistake. That’s why surely Labour’s leadership will now let the public decide.