A clinically obese Frenchman who had been stranded in the United States was on Wednesday taken by ambulance to a British ferry port to continue his journey home.

Kevin Chenais, 22, who weighs 230 kilogrammes (500 pounds) due to a hormonal imbalance, was due to take a P and O ferry from Dover on the southeast coast of England to the French port of Calais, a French consular source said.

From northeastern France, he will be taken to his home town of Ferney-Voltaire on the Swiss border.

Earlier, Chenais had been refused travel home by the Eurostar cross-channel train, after arriving at London's Heathrow airport with his parents when Virgin Atlantic agreed to fly him back from New York.

He had been in the US since May 2012 for treatment for a hormone imbalance and had been set to return home on British Airways last month, but the airline refused to accept him as a passenger, saying he was too heavy.

The family subsequently tried to sail across the Atlantic on the Queen Mary 2, but the cruise ship's owners also refused to have him on board.

After arriving at Heathrow, a visibly exhausted Chenais described the ordeal to return home as “terrible, terrible, terrible”.

“The flight was really hard,” he told AFP as he sat on his mobility scooter at the airport.

“I didn't stop crying for the whole flight.”

Chenais, who was wearing a t-shirt emblazoned with the Stars and Stripes, praised Virgin for flying him out from New York's JFK airport and paying for the economy-class flights for him and his parents.

“That was very kind of them,” he said, “but I was very uncomfortable — I have a lot of problems with the skin on my thighs and the seat was small.”

Chenais and his parents were met at Heathrow by French consular staff who arranged for them to try for a Paris-bound Eurostar train later on Tuesday.

But Eurostar then said that he had been refused travel because of its regulations for evacuation procedures.

“His weight meant that we would not be able to take care of this person or be able to carry him to evacuate him,” a Eurostar spokeswoman told AFP.

She said Eurostar did not have any specific weight limit, but each train has two places for disabled or limited mobility people and the train's staff had to be capable of getting each of those people out in case of emergency.

Chenais was staying at a hotel near the Eurostar terminal at London's St Pancras station while the firm looked for other options including cross-channel ferries and taxis, the spokeswoman said.

Eurostar officials were in contact with the French embassy over the issue, she added.

The family's eventual destination is their home town of Ferney-Voltaire near the Swiss border.

Chenais, who requires frequent oxygen and regular care, had earlier expressed his anger at British Airways and the Queen Mary 2's owners Carnival for refusing to take him home.

“We were all set to take the boat, then they turned us back without even seeing me, without even trying,” he said.

“So I'm really angry — doubly angry because British Airways refused to take me.”

Kevin's father Rene, 62, said his son had been left feeling “empty” when British Airways refused to let him fly. The same airline had flown him to the United States in the first place, he pointed out.

“They took him out there, but they wouldn't take him back,” he said. “This is a case of discrimination.”

The journey was tiring for Kevin and the plane was not specially adapted for his needs, his father added.

“Kevin has always been kind of alone in life,” he told AFP.

British Airways said it would always try to accept a passenger to fly “if it's possible and safe to do so”.

“Unfortunately it was not possible to safely accommodate the customer and the family was offered a full refund,” the airline said in a statement.