British Haulage firms faced £5.87m worth of fines last year as the number of illegal immigrants smuggled into the UK has more than doubled in the past three years.

Official figures have shown that the number of “clandestine entrants” who made their way to Dover and other ports has risen from 1,432 in 2013 to 2,935 last year.

Figures are expected to rise even higher this summer due to increased numbers of refugees in Europe and traditionally the summer months are the peak time for illegal immigrants reaching the UK via ferry ports. Also this year illegal immigrants are targeting less secure ports like Dunkirk, as well as ports in Belgium and the Netherlands.

Haulage firms are liable for a £2,000 on the spot fines for any illegal stowaway found on lorries coming through to the UK. As a result several UK haulage firms have been faced with crippling bills for channel crossings when illegal immigrants have managed to forcibly gain entry into HGV trailers and the backs of other commercial vehicles.

Haulage firms are increasingly turning to the latest camera technology and sensors to alert the driver of a break-in and of movement inside and outside their trailers, so that they are alerted of the presence of stowaways in France before they board the ferry and so they can alert the authorities there, thus avoiding any fines.

As a result, in-vehicle CCTV camera firm SmartWitness have seen a 90% increase in sales of their TruckProtect rear trailer cameras and sensor systems, as well as a 300% increase on interior infrared cameras. The sensors alert drivers when there is movement at the rear of the trailer that automatically turns on the camera that can be viewed in the cab. There are also heat-sensing cameras for inside the trailer which can give night vision footage and detect the presence of bodies. The system will also send a text message to the driver if he is away from the vehicle to let him know there has been a breach of the sensors.

Paul Singh, CEO of SmartWitness said: “Several smaller British haulage firms have been taken close to going out of business by fines for having illegal stowaways completely without their knowledge. Many have been forced to cut their cross channel work during the summer months but the ones that have to continue work on the continent have felt it necessary to increase security measures on their vehicles in order to avoid stowaways breaking into their vehicles at ports in northern Europe.”

In one case last year, a lorry driver was issued with a £19,500 fine, despite calling police when he discovered around a dozen people inside his trailer while driving on the M25. The haulier was offered no reduction in fine whatsoever for informing the authorities and so there is little incentive for hauliers to hand over migrants they may find stowed away in their vehicles.

The Home Office disclosed that over the past three years more than 7,000 people have made their way into Britain through ferry ports. Just over half of them were caught at the ports, while the remainder were found elsewhere in the UK. Last June, 68 people, including 15 children, were found locked in containers aboard four trucks in Harwich, Essex. They had arrived from the Netherlands and included 35 Afghans, 22 Chinese, 10 Vietnamese and one Russian.