Ms Christofferson is grateful to BA

Labour MP John Smith, chairman of the all-party parliamentary group on DVT, told BBC Radio 4's Today programme BA was diverting attention from the case.

On Tuesday, the House of Lords will decide if DVT blood clots linked to air travel can be considered accidents.

BA waived costs, after some victims complained they could not pursue a case

Ruth Christofferson, of Newport, south Wales, whose daughter Emma died two years ago after suffering DVT on a flight from Sydney, told Today they were grateful BA's offer had enabled them to take their case to the Lords.

But Mr Smith - whose constituency, the Vale of Glamorgan, includes Cardiff International Airport - told the programme the airline's "apparent generosity" had a second ulterior motive.

Be very careful of strangers bearing gifts Labour MP John Smith, chairman of the all-party parliamentary group on DVT

"They are very confident they are going to win the case and don't want to seem like the bad guys up against the victims who have suffered so much."

"Be very careful of strangers bearing gifts," Mr Smith said.

BA was trying to "divert attention" from the fact the more than 60 million British passengers flying abroad every year had "no legal protection whatsoever if their health or psychological wellbeing is damaged as a result of flying", he added.

Last year, campaigners hit a major setback when they lost a Court of Appeal bid to overturn a legal ruling blocking their claims for compensation.

The claimants described the decision as a "major blow", but decided to take their fight to the Lords.

We recognise it is an issue of major importance to people and do not want the threat of a big legal bill from BA standing in the way of their right to take it to the highest court in the country BA spokesman

If the Lords rule DVT blood clots can be considered accidents, airlines may be liable.

A BA spokesman told BBC News Online the airline was confident the Lords would rule in its favour, bringing the issue to a "final resolution", but it had promised to waive its legal costs as "a genuine offer made in good faith".

"We recognise it is an issue of major importance to people and do not want the threat of a big legal bill from BA standing in the way of their right to take it to the highest court in the country," the spokesman added.

'Absurd' law

Mr Smith told Today: "I hope and pray the victims are successful in their endeavours to prove DVT is caused by an accident - but they shouldn't have to be proving this at all.

"As many as 1,400 people a year could be dying unnecessarily from this condition in Britain alone.

"The last published study suggests as many as one in 100 air travellers develops a potentially life-threatening DVT," Mr Smith added.

Mr Smith, Ms Christofferson and other victims of DVT are planning to present a petition to the prime minister calling for a change in the law.

The current law, which dates back to 1929, "is absurd and has to change", Mr Smith told Today.