Giles Sheldrick, Express, January 22, 2018

Security insiders said heartbeat monitors, which can identify stowaways in seconds, had not been used at the port for up to six months.

The revelation has sparked accusations that French officials are deliberately passing the buck and have no intention of apprehending immigrants heading for the UK.

The explosive claim prompted calls for an immediate investigation into border security at Calais.

This latest border scandal comes just days after Prime Minister Theresa May pledged French president Emmanuel Macron a further £44.5million of taxpayers’ cash to combat the threat on our doorstep.

Security insiders said heartbeat monitors had not been used for six months

Richard Burnett of the Road Haulage Association said: “The French don’t want migrants to stay in France. They don’t want to provide asylum — in fact, they don’t want to deal with the issue at all.

“It is hard to justify spending another £44.5million to boost security at Calais when we have it on good authority the heartbeat monitors already in place… are not even switched on.”

Despite Britain spending more than £850,000 a day since 2010 defending the border, critics across the Channel continue to claim the UK is not doing enough to tackle illegal migration.

But France’s border police last night denied there was any collusion in helping migrants reach Britain, insisting: “It just doesn’t happen.” Dover MP Charlie Elphicke said, however: “People will rightly be furious if the French are failing to use this vital technology.

“It raises serious questions about why we have handed over millions of pounds to the French. These claims need fully investigating.”

Mr Burnett added: “The migrants know the state of play. The monitors, because they are not working, instead of acting as a deterrent have the complete opposite effect.

“Switching them off encourages migrants to get through and helps them achieve their goal of reaching the UK on the back of a truck.

The revelation has sparked accusations that French officials are deliberately passing the buck

Heartbeat monitors have been used at the ferry port in Calais for more than a decade.

The system detects stowaways using sensors that pick up a shock wave generated by heartbeats.

Searches can take as little as 14 seconds after sensors are placed on a fully loaded vehicle, and monitors are 100 per cent effective in ideal conditions.

But Tony Smith, former head of UK Border Force, said detection techniques in both Calais’ British and French zones “involves a range of equipment including scanners, carbon dioxide detectors, sniffer dogs and heartbeat monitors”.

He added: “All are useful, but some are more appropriate than others in different circumstances. In my experience the heartbeat detectors are extremely sensitive and can be set off by traffic vibration or even seagulls landing on vehicles.”

A source at the French interior ministry confirmed it was “entirely at the discretion of officials” when to use heartbeat monitors, adding: “Not everybody can be checked – that would be an impossibility.”

A Home Office spokesman said: “The operation of juxtaposed controls is in the common interest of the UK and France.”