Britain could face food shortages this summer thanks to the growing migrant crisis in Calais, hauliers have warned.

Freight trucks have already faced severe delays, with queues now five miles longer than the Channel Tunnel itself, as they try to cross into Europe. Now haulage firms say the delays could cause shortages of key supplies, thus causing food prices to shoot up.

The Daily Mail reports that some truck drivers have been stuck in their cabs for days, requiring emergency food and water supplies as well as chemical toilets. At its peak, the queue reached 36 miles and barely moved 500 yards in two days. It is now expected to reduce in length over the weekend, but many drivers will still be stranded for the next few days.

Jack Semple, director of policy at the Road Haulage Association, said: “It is really disrupting supplies. You can no longer guarantee supplies will be delivered on time.

“Companies importing produce, but also components, are switching to air freight which is more expensive. This will also push up prices.”

It is not just delays that could lead to shortages. Migrants clambering aboard trucks carrying food are contamination supplies, sometimes even urinating on them. All contaminated supplies have to be destroyed.

Semple added: “We estimate that the crisis is already costing around £1billion a year in terms of lost produce. Costs are rising rapidly.

“It is inevitable that these rising costs will feed through to the shops sooner or later in the form of higher prices. The migrants are targeting the lorries and clambering on board. But once you get contamination, the whole load is written off.

“That might be worth around £30,000 per load but it could be much more. Nothing can be salvaged as the shops and supermarkets rightly won’t risk it on hygiene grounds.”

Delays also mean that some produce is past its “best before” date before it even reaches the shops, with who truck loads of goods having to be dumped upon arrival in Britain.

Prime Minister David Cameron announced yesterday that the government would be sending extra fencing and sniffer dogs to help with the crisis, a decision widely mocked as too little too late.

Road Haulage Association chief executive Richard Burnett said: “The measures aren’t enough, they are just sticking plasters in terms of trying to resolve this problem.

“Until we actually contain the situation in Calais with the migrants, this situation is a crisis and it’s out of control.”