Britain's decision to quit the EU could lead to a summer surge in illegal migrants trying to enter the country from France, the head of Eurotunnel has warned.

Jacques Gounon, the firm's chief executive and chairman, said Brexit had given migrants a "clear signal" that the Anglo-French border would become "a huge wall, similar to the Berlin Wall, almost impossible to overcome".

He spoke in Calais as the company unveiled new aerial drones armed with cameras to boost security on the French side of the tunnel by spotting potential trespassers.

A pilot prepares a new security drone at Eurotunnel in Calais, as the company continues to face problems with migrants attempting to enter the Eurotunnel site.

Mr Gounon told the Press Association: "I'm afraid that any Brexit consequences could give a threat to migrants that they could be prevented from going to the UK - definitively going to the UK - in the years to come.

"This could generate an additional new migrant pressure, in order for such people, desperately, to reach the UK before Brexit is enforced.

"So I do think and I'm afraid that we could have an increased migrant pressure during this summer, as a Brexit consequence."

Immigration was a key battleground in the EU referendum campaign, with Nigel Farage unveiling a Ukip poster showing a queue of hundreds of immigrants arriving in Europe with the slogan Breaking Point.

The Calais end of the Channel tunnel has been the focus of attempts by migrants to stow away on vehicles headed for Britain.

Earlier this month aid charities reported that the population at the Jungle camp had risen to 6,123 - up from 5,178 in May - including 700 children.

L'Auberge des Migrants and Help Refugees, which collected the data, said refugees from Afghanistan were the largest national group in the camp, making up 36% of its inhabitants, while those from Sudan made up 32%.

In May Downing Street said improved security measures at the tunnel and ferry port in Calais, was behind attempts by migrants to cross the Channel in boats.

Mr Gounon said the firm did not support the idea of moving the UK border from its current locations, as set out in the 1986 Treaty of Canterbury and Protocol de Sangatte in 1991, after Brexit.

He added: "We are working very efficiently, jointly, with UK Border Force on the border issues for 25 years and so I don't believe that for the shuttle, for the fixed link, there is any interest to change the way the controls are working.

"Because it is very efficient, we are catching and giving to the police force all the information in order to protect the site and to capture the migrants. I don't see what could be done more.

"The drones are of course the way to increase the speed. We are working with these border issues, but definitively I think there is no interest at all, from the shuttle point of view, to have an additional border control in Folkestone, at the exit of the tunnel."

Last week Abdul Rahman Haroun, 40, walked free from court after pleading guilty to an obstruction charge brought when he trekked through the Channel Tunnel

Haroun was granted permission to stay in Britain after being caught walking near the end of the 31-mile (50km) sub-sea tunnel at Folkestone, Kent, on August 4 last year.

Judge Adele Williams sentenced him to nine months in jail at Canterbury Crown Court but freed him due to time he has already spent in custody.

After the referendum vote the mayor of Calais Natacha Bouchart suggested that the Touquet agreement of 2003, which keeps border checks - and many migrants - on the French side of the Channel, should be renegotiated.

She told French broadcaster BFM TV: "The British must take on the consequences of their choice.

"We are in a strong position to push, to press this request for a review and we are asking the president to bring his weight (to the issue).