Britain may have to increase its Channel deal payments to France to nearly £1bn because it is such a big draw for migrants, the head of an inquiry has warned.

Sébastien Huyghe, the chairman of a French parliamentary commission into Channel agreements, said that if the small boats crisis continued, France could demand an increase to the current £662m three-year deal to “more than €1bn” (£930m) – a rise of 40 per cent.

Sébastien Huyghe acknowledged the UK was making efforts to minimise its appeal to migrants but said it bore 'significant responsibility' for the crisis

Sébastien Huyghe acknowledged the UK was making efforts to minimise its appeal to migrants but said it bore ‘significant responsibility’ for the crisis – AFP via Getty Images/Alain Jocard

He admitted that he was “not sure” the UK would agree to such an increase in funding, but he maintained it bore “significant responsibility” for the current situation because it was so attractive to migrants.

His commission has estimated that a third of all migrants entering the EU illegally do so because they are targeting the UK, around 60,000 out of 170,000 in 2025.

“We have learnt that 71 per cent of those who manage to cross the English Channel or the North Sea are subsequently granted refugee status, which is a huge figure,” said Mr Huyghe.

“As those attempting the crossing have a high chance of being granted permanent residence on British soil, I understand why they are willing to take every risk.

“Furthermore, although efforts are being made, the UK remains highly attractive due to its labour laws. I therefore cannot see how the situation on our coasts could change in nature.”

“Are the residents of the Opal Coast, the Calais region and even the entire coastline – given that the problem is spreading further and further in Belgium and Normandy – are they condemned to live with this situation ad vitam aeternam [forever]?”

Mr Huyghe, a Republican deputy in the national assembly, urged the French government to “revisit” the 22-year-old Le Touquet agreement between the UK and France under which border checks are carried out before travellers leave each country.

It has been supplemented by the Sandhurst Treaty, the three-year deal under which the Home Secretary agreed to pay £662m to boost French officers on the beaches and at sea, and invest in more surveillance, drones and other technology.

Migrants living in tents in the so-called Jungle in Dunkirk

Migrants living in tents in the so-called Jungle in Dunkirk. Sébastien Huyghe says the problem is extending further along the Channel and North Sea coast – NurPhoto via Getty Images/Nicolas Economou

“If the situation continues, we could find ourselves demanding a further 40 per cent increase in three years’ time, which would bring the total to €1bn,” said Mr Huyghe.

“However, I am not sure that the British would agree to increase funding by 40 per cent every three years simply because their country is attractive.

“There is a consensus within this committee, it seems to me, that the current situation is unsatisfactory and cannot be allowed to continue for years to come.

“One need only visit the Channel and North Sea coasts to see the conditions in which those seeking to reach the UK are living.

“Furthermore, although these people are in an irregular situation in our country, France prevents them from leaving its territory and exiting the European Union, which is a real paradox, especially as a third of those entering the EU irregularly do so in an attempt to reach the United Kingdom.

“I find it rather difficult to understand why we are allowing this situation to continue.”

Meanwhile, France is seeking to end the one in, one out scheme, which is due to expire on Oct 1, although the UK is seeking to continue it as a deterrent to crossings.

Laurent Nuñez, France’s interior minister, said he wanted to replace it with a “broader” returns deal between the UK and the EU so that the burden was shared across member countries rather than France alone.

He also opposed scrapping the Le Touquet agreement because of the risk that it could lead to a “massive influx of migrants on to the coasts of the English Channel and North Sea”.

In an effort to make the UK less attractive to migrants, the Government has doubled the number of arrests for illegal working in two years.

It also ended the permanent right to refugee status with reviews every 30 months of the right to remain in the UK, and plans to double the time before migrants can get indefinite leave to remain from five to 10 years.

Try full access to The Telegraph free today. Unlock their award-winning website and essential news app, plus useful tools and expert guides for your money, health and holidays.