People who cross the Channel on "booze cruise" excursions are being jailed in France after being tricked into smuggling illegal immigrants, a former prisoner has said.
The arrests of booze cruisers has helped to drive up the annual number of Britons being held in foreign prisons accused of people trafficking.
Some of those apprehended after making trips to buy cheap alcohol at cash-and-carry outlets in France claim they were tricked by organised crime gangs or by desperate and opportunistic asylum-seekers.
The charity Prisoners Abroad said 46 Britons had been jailed in the past three years, mostly in northern France. Avan Wadia, of Prisoners Abroad, said: "[We] have recently seen a dramatic increase in the number of people arrested for smuggling illegal immigrants, rising from only four in 1998 to 27 in 2000."
She said traffickers were being offered £2,000 per person smuggled and told that risks were less than those involved in drug smuggling.
Ms Wadia said: "As border controls tighten, the number of arrests will inevitably continue to grow. People need to think about the consequences of getting involved in such activities, as Prisoners Abroad is seeing more and more prisoners and their families devastated."
Some of those jailed claim to be innocent. Nick Clarke, a security guard from Tottenham, north London, returned to Britain last month after serving 10 months at Longuenesse prison in Lille.
According to Mr Clarke, he and a friend, Ronald Duberry, had crossed the Channel in a hired van last Christmas Eve to buy cheap alcohol and presents for the holiday period.
They were arrested on a ferry as it was about to leave Calais after French officials asked to inspect the van.
Mr Clarke, 28, said: "We said, 'No problem'. But when they went to check it a load of people fell out the back. There were 28 in there. Babies and whole families. I couldn't believe it, it was just a joke. The shock of it actually made me smile."
The Britons and asylum-seekers were arrested and questioned. Mr Clarke said he was still expecting to be allowed to board a ferry when an interpreter told him he could be facing five years in jail.
The French authorities were not convinced by the two Londoners' story. After spending Christmas Day in a police station, Mr Clarke was sentenced to 15 months. Mr Duberry, a transport worker, was given six months.
Still adamant of his innocence, Mr Clarke says he has no idea who the asylum- seekers were or how they came to be in the van. He said: "They looked like Turkish or Kurds but they could have been Albanians. I don't know. We didn't speak to them and they didn't speak to us.
"I realise now that the asylum-seekers are desperate. They will leave no stone unturned to get to England."
The pull-down shutter at the rear of the van was unlocked and the Britons had broken their journey three times, to stop for petrol, food and buy their tickets at the port.
In prison, Mr Clarke and Mr Duberry met other Britons jailed for similar offences. One claimed to have been arrested for "aiding and abetting" illegal immigration after being seen by police giving money to an asylum-seeker, who he claimed had asked him for a train fare.
Neriman Sengul, a minicab driver from south London, spent three months in prisons in northern France after being accused of being involved in a smuggling racket last year. Mrs Sengul, who has five children, said she had thought she was taking part in a booze cruise run but was duped by someone she considered to be a friend.
After driving to a cash-and-carry near Calais, she loaded up with drink. Some associates in a van, who were to buy tobacco from a warehouse, asked her to show them the way. She parted company with the van at a car park near Dunkirk where she handed over money she had been told by her friend was to pay for the tobacco.
Mrs Sengul, 52, was arrested a short while later by French police who had been tracking the group and had filmed the payment in the car park.
She says she had no idea her associates were carrying would-be illegal immigrants. "They arrested me for conspiracy. I know in my heart, and everyone around me knows, I'm not guilty. This has ruined my life," she said.
Mrs Sengul was jailed before being freed on payment of 5,000 French francs (£500). She said: "I was with murderers and drug dealers. My only crime was showing people the way."