BREXIT should be sorted by the people, not politicians, Labour’s Brexit mastermind said yesterday on a visit to the key marginal seat of Darlington in what is being called the “Brexmas election”.

“This is no longer a decision for politicians,” Sir Keir Starmer said. “We have got stuck for three-and-a-half years in Parliament. Therefore, if we leave with our negotiated deal or we remain is for members of the public to decide.

“The decision maker is no longer Parliament – it is over to the public.”

He was speaking as several south Durham Conservative candidates sent letters to their Labour opposite numbers ahead of the December 12 poll asking: “What is your plan to get Brexit done?”

Responding, Mr Starmer said: “I can do Labour’s Brexit policy in 10 seconds and three sentences. We’ll secure a better deal than Johnson’s deal. We’ll put it to a referendum against remain. We will do that within six months.

“People may agree or disagree, but you cannot say it is not clear.”

Mr Starmer has been working with the EU on Labour’s alternative deal, of a customs union and single market alignment with protection for workplace and environmental rights, for three years, with the Darlington Labour candidate, Jenny Chapman, as part of his team.

The basis for his deal has been shaped, he said, by visits to the North-East. “I was very struck at Hitachi (at Newton Aycliffe) and by all our manufacturers on how reliant they are on the customs union. In the North-East, management and trades unions were saying the same thing – they need a customs union to preserve their way of working.”

He is “genuinely confident” that his deal can be secured within three months, and then it would go to a referendum – where he would probably vote to remain.

“I don’t think it is a problem,” he said. “Whether you want to vote for remain or to leave, you want the best leave option to be available.”

The Labour Party would hold a special conference to determine its position at the referendum. “My reading of the membership is that it is very pro-remain and always has been, and I think it is likely that the party would want to campaign for remain,” he said.

But, if he were Prime Minister, Jeremy Corbyn would be neutral. “He wants to sit above it because he knows how divided the country is, families are, communities are, regions are. Someone needs to say ‘I have passed the decision to you, I will faithfully implement it’.”

Mr Corbyn would act as an impartial arbitrator, but he could be accused of having no opinion on the biggest issue facing the country since the war, and of not actively campaigning for what the party wants.

“Those are manageable issues,” said Mr Starmer. “We will have MPs representing areas that voted heavily for remain and heavily for leave. We need to manage those tensions, but the important thing is that it is not us making the decision – it is the public making the decision.

“People are yearning for there to be some certainty, for there to be an outcome. Leave voters need to be assured that if it is a leave vote, there is no more delay, the legislation is in place, we will leave within days.”

He said Boris Johnson’s withdrawal deal would cost thousands of jobs, and said the Prime Minister’s insistence that he could get Britain’s future trading relationship with the EU sorted within months as “pie in the sky”.

“He isn’t going to complete it by next December and he knows it,” said Mr Starmer. “A responsible PM would say this is going to be difficult, that trade deals take years and I am going to make it as swift as possible – that would be the honest approach, but the PM doesn’t take it.

“People need to see through this because whatever your political colours you need a PM you can trust.”

Darlington is the 31st most vulnerable seat in the country to a Conservative swing, and its neighbour, Bishop Auckland, is the eighth. In their letters yesterday, both Tory candidates in the seats said they had pledged to back Mr Johnson’s deal in Parliament.

“The Labour plan to stay within the customs union is not what people voted for – they voted to leave,” said Peter Gibson, the Darlington Conservative candidate. “Why can’t Labour MPs accept the result of the referendum, that the people here voted to leave?

“How can the Labour Party leader remain neutral on such a big issue? If you leave a car in neutral it will not go forwards and it will not go backwards, and that’s what will happen here.”