A NORTH-EAST expert who has studied so-called "economy class syndrome" - where long-distance aircraft passengers develop potentially fatal blood clots - says the problem also affects computer users.

Dr Patrick Kesteven, a consultant haematologist at the Freeman Hospital in Newcastle, says he sees similar deep vein thrombosis (DVT) cases in people who regularly spend long periods in front of a PC.

"We are seeing cases from people sitting at a computer for 12 hours at a time," said Dr Kesteven, who has carried out research into links between flying and DVT.

The consultant says the problem, which claimed the life of 28-year-old Emma Christoffersen last week, after a 20-hour economy class flight from Australia - is caused by sitting for long periods without moving their legs.

"When you are travelling you are forced to sit still for long periods, and that is why there seems to be a link between DVT cases and travelling, but the same problem can occur in other situations," said Dr Kesteven.

"The majority of patients with DVT we see are from aeroplanes, but we are also seeing a handful of cases from bus travel and a few more from cars," said Dr Kesteven, who is planning to organise a before-and-after test for DVT on transatlantic air pasengers, by monitoring a group of volunteers on a new aircraft being delivered to Britain.

He was unimpressed by a claim made by a Dutch doctor writing in The Lancet that his research showed that "economy class syndrome" was a myth and there was no link between DVT and air travel.

"They have failed to find a statistical link between a group of DVT patients and travel. That is a long way from proving that there is no such link. All they have done is show that the link is very slight," said Dr Kesteven.

While the risk of DVT and air travel was very small "it is a risk that applies to a very large population so there will be a significant number of patients affected," he added.

The consultant advises people who are sitting still for a long period, to stretch their legs and move their feet to reduce the risk of DVT.

Asked whether it is an advantage to be a fidget Dr Kesteven said: "Yes, definitely, but it will probably drive your partner crazy."