A boy was among 15 immigrants found trapped in a tanker on a P&O ferry at Dover Docks, it emerged today.

The child and 14 men were discovered trapped inside the vehicle carrying a food powder yesterday morning.

Two immigrants were taken to hospital and 11 others were treated by paramedics after a dramatic rescue when other lorry drivers heard banging noises from the tanker.

The discovery sparked a major contamination alert and full-scale emergency response.

Now the boy has been handed over to social services and the other immigrants are having their asylum cases prepared.

A Home Office spokesman said: "There were 15 illegal entrants. Twelve were Syrian nationals, two were from Kuwait and one from Afghanistan. All were male.

"One has been released to the care of social services as he is a minor and the rest are having their cases prepared."

Scroll down for video

Port of Dover Police arrested two lorry drivers after the alarm was raised at 8.45am when the P&O ferry Spirit of France arrived at the Eastern Docks from Calais.

A full-scale emergency operation swung into action - with six fire crews and specialist equipment rushing to help with the rescue operation.

Several ambulances and police also attended, together with staff from the Border Control Agency and Revenue and Customs.

Seven asylum seekers received medical attention from paramedics and the authorities confirmed two were taken to hospital for treatment.

Documentation revealed the tanker was carrying a food powder - probably a maize derivative - but the emergency services were taking no chances and tests were carried out to ensure it was non-hazardous.

The powder found in the vehicle was later confirmed as non-hazardous and fire crews left the scene at about 11.15am.

The pair taken to hospital were treated and released by early afternoon.

Yesterday, Dover MP Charlie Elphicke spoke of his fears that the group could have suffocated.

He said: "I'm shocked that they were in this tanker and I'm concerned they could have suffocated. It's exceptionally dangerous.

"Considering what happened a few years ago with that container with Chinese illegals in it, disaster has been narrowly averted yet again.

"I'm deeply relieved that they're still alive, but it is a deep concern.

"We owe real congratulations to lorry drivers who raised the alarm and the emergency services who acted so quickly."

Video: Full-scale emergency response at the Port of Dover

A spokeswoman for the the Port of Dover confirmed that a "critical incident" was launched and that it was being dealt with by the port's own police force.

P&O Ferries said passengers on other sailings experienced delays of up to 60 minutes because of the alert.

News of the discovery brought back chilling reminders of the 58 Chinese people found dead in a lorry at the docks in 2000.