Chaos in Calais as migrants mob lorries

Illegal migrants disembark from a truck in Calais, after failing to cross the English Channel. Photo / AP

Dystopian scenes as vehicles stranded by French ferry workers’ strike are swamped by thousands of illegal immigrants trying to get into Britain.

Illegal migrants desperate to get into Britain have exploited the closing of Calais and travel chaos on both sides of the English Channel.

Thousands of migrants who have massed at the French port used a wildcat strike by French ferry workers to try to clamber on to trucks bound for Britain that were left queuing for hours.

Hundreds of migrants lined junction 42 of the A16 motorway, the main entrance for cars and trucks taking the Eurotunnel to Britain, approaching trucks in small groups and trying to board by all possible means.

Vastly outnumbered by the migrants, riot police did their best to keep them at bay and away from the trucks, hundreds of which were stuck in a huge tailback because of the closure of the Channel tunnel.

The trucks were either stationary or moving at a snail's pace as trains ran again after the industrial action.

Services through the Channel tunnel were also suspended because of the chaos and after French protesters trespassed on to the tracks.

Eurotunnel confirmed it was the first time services had been suspended because of protesters on the track.

British Prime Minister David Cameron was in "close touch" with the French authorities and was likely to raise concerns about the scenes in Calais at an EU summit this morning.

A spokesman for Cameron said a "comprehensive approach" was needed to reduce the flow of migrants as part of a "long-term challenge".

"What you are seeing is the challenge posed by migrants coming from other parts of the world seeking life here in Europe," the spokesman said.

"We shouldn't underestimate that this is a long-term challenge."

Witnesses described "catastrophic scenes" as stranded motorists were warned to keep their doors locked.

Queues in France ran for kilometres after the French ferry workers blockaded the port and set fire to tyres.

Truck drivers were advised not to stop within 95km of the port, and to make sure padlocks were kept on vehicles.

In Kent, lorries were queuing for several kilometres on the M20 to Dover after police implemented Operation Stack, where freight traffic is held on the coastbound carriageway.

The Foreign Office and Home Office were monitoring the situation closely as one British haulier said the situation was the worst he had seen.

The chaos comes amid deep concerns over the growing numbers of illegal migrants who are camped at Calais - now more than 3000.

At least 2000 more could arrive over the northern summer and many will try to get into Britain.

Eurostar passengers stranded in London. Photo / AP

It came as Britain's National Crime Agency warned the illegal immigration problem was set to deepen.

"Detections of irregular migrants attempting to enter the UK clandestinely more than doubled in 2014," said a report by the agency. "This is likely to continue on an upward trend."

The Home Office said the UK Border Force and the French authorities prevented more than 39,000 attempts to cross the Channel illegally in 2014/15, twice the number in the previous year.

Motorists described how the desperate people lined the routes, trying door handles and attempting to climb on.

Donald Armour, international manager at the Freight Transport Association, said the situation was "definitely worse than it has ever been".

"There is a lot of fighting between the migrants who all want to be on the best part of the road to get on to the lorries," he said. "We haven't had a fatality but it's not good."

The French ferry workers are striking over fears they are to lose their jobs next month - they brought the major port to a standstill.

British haulier Chris Cary said he had been stuck in Calais for seven hours. He told Sky News: "When I was down at the train, [migrants] were trying your doors to get in the cab, trying to sneak under the axles on the trailers, trying to cut the locks and seals on the back of the trailers, even trying to climb on the roof of the trailers."

Gilles Debove, of the police union Unite SGP-Police FO, said: "The police were more occupied with dealing with the strikers trying to stop the traffic, so the migrants were having a field day because there were very few officers left to stop them."

He said there were roughly 1000 migrants trying their luck around the entrance to the tunnel.

The Home Office said funding was being provided to boost security and infrastructure at ports in northern France and Belgium.

"Law and order in and around Calais is the responsibility of the French authorities, but the UK continues to work with its French counterparts to strengthen the security of the border to stop illegal immigrants entering the UK," a spokesman said.

"We are providing funding to bolster the security and infrastructure of ports in northern France and Belgium.

"We have also installed new fencing in Calais to enhance security at the port and help protect traffic on the road leading to it.

"We are also tackling the roots of this problem by increasing joint intelligence work with the French to target the organised crime gangs behind people smuggling."