Emmanuel Macron persuades Theresa May to take more 'humane approach' to child migrants from Calais

French President also issues strong warning that the EU would not allow British ‘hypocrisy’ in seeking to keep the economic benefits of membership after Brexit

Child migrants seeking to escape Calais and come to Britain will have their claims processed within 25 days, after French President Emmanuel Macron persuaded Theresa May to adopt what he called a “humane approach”.

The leaders announced a new treaty designed to ease the suffering of some of the thousands of people camped near the French port who currently wait six months to have their cases settled.

It came as President Macron issued his strongest warning yet that the EU would not allow British “hypocrisy” in seeking to keep the economic benefits of membership after Brexit.

Insisting the priority would be to “preserve” the single market, he told a joint press conference: “The choice is on the British side, not my side.

“If you want access to the single market, including financial services, be my guest. But you need to contribute to the budget and acknowledge European jurisdiction.”

To enjoy the full fruits of the single market Britain would have to accept a Norway-style arrangement, which includes free movement of people, he said, adding: “Such are the rules.

“There will be no hypocrisy in this respect otherwise it will not work. It would destroy the single market and its coherence.”

The deal on migrants – to be called the Sandhurst Treaty, Mr Macron said – was the key announcement of the summit, which focused on defence and security co-operation.

However, No 10 was keen to play down suggestions that Ms May had agreed to accept more migrants, insisting it would simply speed up the process of settling claims.

The much-criticised cap on unaccompanied minors would remain at 480 – not 3,000 as originally expected by the so-called “Dubs scheme”, a spokesman said. Around 220 have arrived so far.

The key change would benefit those seeking to join family members in the UK, with children’s cases settled in 25 days and adults’ in one month – instead of a typical wait of six months.

Mr Macron said the agreement “will enable us both to have a more humane approach to these people and to be more efficient”, while also making trade through the Channel ports easier.

Referring to the misery of the now-cleared “Jungle” camp, he added: “We shall put an end to the situation we have been facing for a number of years.”

Despite the removal of the sprawling camp, an estimated 400 people remain in the area, hoping to cross the Channel and reach the UK.

Britain had already agreed to spend £44.5m to boost security at the French port – the price to be paid for border controls to remain on the French side of the channel.

The cash – strongly criticised by right-wing papers - will help pay for security fencing, CCTV cameras and "detection technology" in Calais and at other ports along the Channel.

It has not yet been revealed how much France will contribute towards the new security measures in return.

Ms May defended the decision to spend many millions more in Calais, saying: “What we are doing is working with the French authorities and providing support to ensure that we enhance the security of our border.

"This is in our national interests, it is also in the interests of France to ensure that we have as secure a border as possible at Calais and other ports."

On Brexit, asked how Britain could change the mind of the EU and its apparent refusal to include financial services in a deal, Ms May swerved the question.

Instead, she restated her call for a “deep and special partnership” and a “comprehensive trade agreement” between the UK and EU, in both sides’ interests.

“I think the City of London will continue to be a major global financial centre. That is an advantage not just for the UK, it's actually good for Europe and good for the global financial system,” she argued.

Mr Macron’s tough stance underlined his position as probably Britain’s staunchest opponent in the Brexit negotiations to come.

There are strong suspicions that Paris is determined to stretch out the negotiations, to heighten the uncertainty for UK businesses and make it more likely they will move to France.

Earlier, the Prime Minister entertained the French president at the 17th Century Royal Oak pub in her Maidenhead constituency, where they dined on a menu of dressed crab, blood orange radicchio and sorrel followed by Creedy Carver duck breast, roasted onion tartlet and beetroot puree.

The meal was prepared by last year's winner of the BBC's MasterChef: The Professionals, Craig Johnston, who at 21 was the youngest winner of the contest.

But the two leaders were forced to inspect the troops in the freezing rain at the start of the summit, at the Berkshire military academy, when the skies opened for the guard of honour.