A world-first revolutionary windpipe transplant operation was nearly scuppered when budget airline staff refused to allow stem cells on to a plane, it was revealed yesterday.

A world-first revolutionary windpipe transplant operation was nearly scuppered when budget airline staff refused to allow stem cells on to a plane, it was revealed yesterday.

Professor Martin Birchall, who grew the cells for the revolutionary procedure, was forced to pay £14,000 for a private plane after easyJet refused to give flight clearance to Barcelona.

Prof Birchall, of Bristol University said easyJet's last-minute "no" followed months of double-checking to ensure the priceless package was permitted to travel.

The team was left with 16 hours to get 30-year-old Claudia Castillo's cells to Spain so paid £14,000 to hire a jet piloted by a medical student's friend.

The airline insisted it had no record of a request for security clearance to transport the cells, which are carried in a liquid to protect them. However, it has agreed to refund the flight costs "as a goodwill gesture".

In a pioneering process, stem cells from Mrs Castillo's bone marrow were used to create cartilage cells which were then combined with part of a donor's windpipe, creating an artificial trachea in the lab. The procedure was the world's first tissue-engineered whole organ transplant - using a windpipe made with the mother-of-two's own stem cells.

Five months later, Mrs Castillo, from Colombia, is in good health and can now converse with her family without losing her breath. She needed the transplant to save a lung after contracting tuberculosis.

Prof Birchall said he was "furious" at the refusal and was nearly arrested by armed police while frustratedly trying to explain the situation to staff.

EasyJet spokesman Andrew McConnell said that requests for cell and organ transport are usually dealt with through the company's call centre in Poznan, Poland.

Doctors would then be advised to call the United Kingdom Transportation for Transplants (UKTFT), who would then arrange clearance with the airline.

However, in this case doctors are understood to have called the company's UK head office direct, he said.

Mr McConnell said that although there was no record of a request to transport the stem cells anywhere in the files, he would "rule out" the possibility of administrative error.

Mr McConnell said: "We have an established process to transport human organs. We work with the United Kingdom Transportation for Transplants.

"UKTFT would contact our international flight control centre in Luton to inform us of their intention to transport human organs.

"The police will also be involved to verify the origin of the consignment.

"A record of the request would have then logged on to the passenger's booking.

"We do not have any record of the passenger's request to carry medical materials on board the flight. However, as a gesture of goodwill. we have refunded the passenger for the cost of his easyJet flight."

There was just a 16-hour window during which the cells could be transported before they would become useless.

For that reason, Prof Birchall said he had had several conversations with the airline leading up to the key moment, to ensure things would go smoothly.

Professor Anthony Hollander, another of the scientists involved, said that after a lengthy debate, check-in workers refused to take the cargo, fearing it could be "dangerous material".

A German medical student, Philip Jungerbluth, who was going on the flight, saved the day as he knew a surgeon in his home country with a private jet. The new pilot did not hesitate to take on the unusual charter and was in Bristol within two hours.

The university's research communications manager Cherry Lewis said neither the university nor the doctors involved would be commenting further as they were now concentrating on a research proposal.

Earlier Prof Birchall, an ear, nose and throat surgeon, told the BBC: "The clock was ticking as we'd taken the cells out of their culture media an hour before. We thought about driving to Barcelona, but that would have taken too long.

"If we hadn't been able to get the cells there, we would have wasted years of work and this major breakthrough wouldn't have taken place."