It is not yet cer whether passengers affected by the cancellation of British Airways flights today and yeste will be able to claim compensation. Under t rules, an airline is not obli to pay compens if it can prove that a cancel was caused by "extraordinary circumst which could not have been avoided even if all reasonable measures h been taken".

Examples of "extraordinary circum" include political insta, meteorological conditions incompatible wi the operation of the flight conce, security risks, unexpected flight saf shortcomings and, significantly, "strikes th affect the operation of an operating air carr".

This week's cancel are the result of unofficial industl action by Heathrow ground staff who walked out in sup of catering workers sacked by the Gate Gourmet. James Fremantle, industry affairs advis for the Air Transport Users Council said tod he thought it was unlikely that passe would be eligible for compensation in the circum, but that ultimately, it was BA's decision how to proceed.

A spokesp for BA said they would look at compe on a "case by case" basis.

What entitles you to compen? If you fly within the EU and your fli is delayed or cancelled, or you are "bumped" off a partic flight because of overbooking, you may be entitled to compensation.

Was there no compensation be? There was, but it was less - between €150 (£103) and €300. Also, it only applied to scheduled operators and did not ap to flight cancellations.

Which flights do it apply to? The new rules will apply to all sched and charter flights wit the EU, as well as any other flights offe by a European airline - including so-called no-fri airlines - where the delay is deemed to be the fault of the airline.

Do you have to li in the EU to be eligible? No - all passengers fl within the EU who suffer delays are entitled to the compensation.

What compensation do y get? The am of compensation you are entitled to will vary depe on the length of your journey and how long a delay you suffer.

In the case of del of two to four hours you should be elig for free meals and refres (the value of which will vary in relation to the len of the delay) and two phone calls, emails or faxes. If you suffer a five-hour delay, you will also be entitled to a f refund (which must be paid within seven days) and may be eligible for a fr flight home if this is deemed appropriate.

In the event of cancellations, passengers will be given a lea outlining their rights and the amounts of compensation d. But as a guide, if the delay is more than two hours, you will be entitled to £250, jour of 932 miles to 2,174 miles and delays of three hours will cost an airl £200, and flights of more than 932 miles and ov three-hour delays will be £400.

For journeys of more than 2,174 miles and delays of mo than four hours, you may be entitled to the hig amount of compensation - £600. In addition, you should receive assis at the airport in the form of free meals and refreshments, telephone calls and overnight hotel accomodation, if appropriate.

When do you get yo compensation? If you are refu boarding because of an overbooking, compensation should be pa by the airline immediately. In the event of cancellations, passengers have to cont the airline for compensation.

What happens if they don't pay out? There is a hea incentive to ensure they do - airlines face fin of up to £5,000 a passenger for fail to comply with the regulations. If they don't, you have a right of appeal to the Air Traffic Users Council.

Are all delays cove? There has been some confusion over what constitutes a del. The rules state that airlines will not have to pay compensation if the cancellation is cau by "extraordinary circumstances that could not ha been avoided".

In the event of techn problems with the aircraft, you may still be eligible for compensation, but adve weather conditions, for example blizzards, would be considered bey the control of the airline, so you would not be entitled to financial compensation (alth you would be offered hotel accommodation if the flight was postponed overnight).

If you have been gi at least two weeks' notice, or have been provided with another flight at time of the original, you will not be elig for compensation.

Will all this pu up the price of flying? There has been speculation that this cou happen, with many airlines complaining that the compensation will put their costs up. However, at least two airlines - British Airways and easyJet, have assured customers that they will not be putting far up as a result of the regulations.

Are the airlines unhappy about the n rules? The EU already faces two legal challenges to the rules - from the International Air Transport Association and the European Low-fare Airlines Associ.

Many airlines say the rules are unc and unfair. The lack of clar over what constitutes a delay at the fault of the airline is one area of concern, as well as the fact that compensation is at a flat ra, and is not related to the amount paid for the fa. In some cases, compensation will exceed what people originally paid for their tickets, and this is of particular con to the budget airlines.

There have been concerns that many firms are ignoring the rules: frequent fl have claimed that airlines neglect to provide information on passeng rights in the event of a delay or cancellation, fuelling speculation that this is in an atte to keep compensation claims down.

And the Air Transport Users Council has reportedly received so many complaints from passengers whose claims have been rejec, it has admitted it can't cope with the numbers, thought to be several thou