The High Court in Britain has delivered a severe setback to 24 victims of Deep Vein Thrombosis (DVT) by barring them from suing some of the world's largest airlines.
They had appealed against a court ruling last year which stopped them proceeding against the carriers.
The 18 carriers involved in the case include Europe's largest, British Airways, and US firms Continental Airlines and Northwest Airlines Corp.
Speaking on behalf of the victims of DVT, or "economy class" syndrome, solicitor Mr Desmond Collins said they would take their case to the House of Lords - England's top court.
They had appealed against a High Court decision last December that struck down their attempt to sue more than 25 airlines for the sometimes fatal blood clots that they blame on long flights and cramped seats.
Today's move is a setback for other DVT sufferers pursuing similar cases against airlines in the United States and Australia.
It also reduces the likelihood that the airlines will have to pay out huge sums in damages around the world.
The claimants say airlines have known for years about the dangers of DVT blood clots, which can sometimes invade the heart or lungs and cause death. But the carriers contend DVT is not a flying disease.