Research into alleged links between long-haul flights and deep vein thrombosis (DVT) by scientists has been shunned by airlines, is has been alleged.
Five scientists studying deep vein thrombosis (DVT) in long haul flights had their separate requests for information from airlines refused or ignored, they told BBC1's Panoramaprogramme, being broadcast tonight.
According to recent research, up to one-in-10 people travelling on long-haul flights could develop blood clots.
DVT is also known as "economy class syndrome" and occurs when a small, potentially fatal blood clot forms, often in the deep veins of the legs.
It is dangerous and potentially fatal if part of the clot moves and blocks a blood vessel in the lungs or the brain.
Scientists are concerned that flying presents a risk because of the long hours a passenger remains immobile.
Airlines have been criticised in the past for not offering enough information to passengers about the condition, which is estimated to kill up to 1,000 Britishtravellers a year.
Professor Sam Shuster told the programme: "There is the added difficulty that we have to tread carefully because as a commercial organisation we have no wish to imply that flying might be bad for one's health."
Experts have estimated that DVT affects up to one in 10 long haul passengers and the Department of the Environment, Transport and the Regions set up a study on the possible risk of DVT during air travel earlier this year.
In Britain the problem was highlighted recently following the high profile case of 28-year-old Emma Christofferson, from south Wales, who died following a 20-hour flight from Australia.
Ms Christofferson suffered a massive blood clot and collapsed and died shortly after arriving at Heathrow Airport in October 2000. She had slept for most of the journey. PA