A carbon dioxide detector that alerts drivers to immigrants hiding in their lorries went on sale in Britain on Tuesday, aimed at freight companies concerned by a surge in attempted Channel crossings.
Migrants based in the French port of Calais try in their hundreds each day to board Britain-bound lorries, prompting confrontations with drivers who risk being fined for transporting them or having their cargo spoiled.
In response, a British company has developed a device that measures CO2 levels in the lorry and alerts the driver and the freight company to any changes via SMS or email.
"The unit will detect within about a tenth of a second whether anybody -- human or animal -- has got into your trailer," Matthew Perryman, business development director of 360 Advantage, told AFP.
He said the driver could then call the police, who could remove the migrants with a minimum of disruption.
Perryman said the "unique" device was developed after discussions with the Freight Transport Association industry body about the migrant issue.
"At Calais it's got out of control," he said, adding that the tracking system worked all over Europe.
The FTA currently has an exclusive deal to sell the £299 (426 euro, $465) device on its website and Perryman hopes to sell about 5,000 units over the next two years.
"Anything that makes it safer for drivers to do their job is to be welcomed," said FTA deputy chief executive James Hookham in a statement.
"This sensor removes the need for them to check their own trucks –- something that puts them in serious danger in Calais where there are thousands of migrants milling around."
British Home Secretary Theresa May said that more than 8,000 attempts by migrants to travel to Britain from French ports were intercepted by officials on both sides of the border in less than a month between June 21 and July 11.
This compared with earlier figures showing 30,000 attempts over a 10-month period to January 2015.
Many of those who attempt the crossing are fleeing Syria or other conflict zones but it is risky, with at least four people losing their lives in recent weeks.