LONDON, Dec 20: A London court blocked an attempt on Friday by victims of “economy class syndrome” to sue airlines over claims that cramped seating on long flights gave them potentially deadly blood clots.

In a ruling with important implications for airlines worldwide, the High Court said blood clots did not constitute an “accident” under the Warsaw Convention. The 1929 treaty makes airlines liable for damages only in the case of an accident.

The decision, which ran counter to a ruling made earlier on Friday in a similar case in Australia, was based on reasoning by Justice Robert Nelson that an “accident” was an unexpected and unusual event “external to the passenger”.

“There was no unexpected or unusual event or happening,” the judge said.

“DVT cannot be regarded as anything other than a serious personal injury, leading, as unhappily on occasion it does, to death.”

Victims have until Jan 28 to appeal the decision which for some families will involve finding the money to continue.

“We’ve got to find the finances now to take this forward, and we will,” said Ruth Christophersen, whose 28-year-old daughter, Emma, died on a flight from Australia to the UK in Sept 2000.

“When we heard the ruling, we were disappointed,” she said. “Not just for myself but for all the people around the world waiting with baited breath on the outcome of this.”

The case was launched by 55 victims and their families against 27 airlines, including Europe’s biggest, British Airways and Europe-based rivals KLM Royal Dutch and Virgin Atlantic.

Major U.S. carriers American Airlines, United Airlines, Delta Airlines and Northwest Airlines were named in the suit, as were Japan Airlines, Qantas Airways Ltd and Singapore Airlines.

AUSTRALIA RULING: Earlier on Friday, an Australian court took the opposite view and gave the green light to a lawsuit there against Qantas and British Airways over a blood clot suffered by a passenger on a long flight.