BA flights chaos after IT meltdown - your rights

The problem, which affected more than 75,000 passengers, first hit on Saturday 28 May, with BA grounding all planes from Gatwick and Heathrow and delays continuing in the following days.

The airline has said it will "fully honour" its obligations under EU flight delays law, meaning many could be able to claim between £110 and £530.

We've detailed help below, but for the full lowdown see our Flight Delays guide, including our FREE Flight Delays and Cancellations Reclaim Tool.

Will my food/accommodation be paid while I was stuck at the airport?

Yes – under EU regulation 261/2004 airlines have to provide assistance such as food, phone calls and accommodation (where there's an overnight delay) to passengers whose flight has been cancelled, while they wait for an alternative flight. They should also usually provide this after a delay of two hours on short-haul flights, three hours on medium-haul and four hours on long-haul flights.

Where the airline doesn't provide you with food, accommodation and so on directly, you can claim back. BA says you should have kept receipts for food, transport or accommodation and can make a claim via its customer relations team in due course. It doesn't stipulate how much it's offering passengers to cover food and accommodation but says it'll cover "reasonable costs".

Can I claim additional compensation for cancellations or delays under EU rules?

Yes, you may be able to. Under EU regulation 261/2004, if your flight was delayed by more than three hours or cancelled, and it was the airline's fault, you can often claim between £110 and £530 in compensation. To qualify, your flight must have left an EU airport, or arrived at an EU airport on an EU airline.

In this case, BA says it's been providing customers with information on how to apply for compensation and has said it will pay out to those affected provided the flight meets the usual EU criteria. It has confirmed it has already made some payments but declined to say how much has so far been paid. If you've tried to claim, let us know how you've got on at news@moneysavingexpert.com.

Here's what you can claim:

• For cancellations you can claim compensation ON TOP of the refund or new flight BA offers, if the alternative flight it offers arrives later than your original flight (even if you choose a refund instead). See Cancellation compensation amounts.

• For delays your flight must have arrived 3hrs+ late. Compensation's fixed, based solely on delay and journey length. See Delay compensation amounts.

For full help on the rules plus our free reclaim tool to demand compensation, see our Flight Delays guide.

It's also worth noting that BA has admitted it wrongly denied compensation to a passenger who was delayed for 19 hours, and that the blunder could have affected passengers on eight separate flights. See our BA compensation blunder MSE News story for more information.

What about hotel/car hire bookings I lost due to my missed flight?

Flight cancellations or delays can have a large number of knock-on costs, and unfortunately the EU rules don't cover what's known as 'consequential loss' – ie, if you've booked non-refundable hotels, car hire or other parts of your holiday and then are unable to use them because your flight's delayed.

British Airways has said it will consider these claims on a case-by-case basis, but you could also check your travel insurance. Some policies, especially those offering fuller protection, may cover you, often under what's known as 'abandonment protection'. Other policies won't. Some insurers set their own timescales as to when cover kicks in, for example if you're delayed by at least 24 hours.

A spokesperson for the Association of British Insurers told us: "The main purpose of travel insurance is to cover emergency medical expenses and other travel-related expenses like baggage loss, rather than systemic computer breakdowns like this situation."

We asked some of the biggest insurers if they would cover passengers caught up in the BA problems. They all said you must contact BA first, but some are considering claims:

Major insurers' policies

We've also previously heard of a small number of cases where people have successfully claimed from their credit card companies for consequential losses using the Section 75 law, which protects purchases made on plastic of between £100 and £30,000. It's likely these claims would be decided on a case-by-case basis, see our Section 75 guide for full information.

Could I sue BA for losses?

If you're not covered by your travel insurer – or are, but really think it should be BA that pays – in theory you could look at suing the airline for consequential loss, in small claims court or civil court for larger claims.

However, in practice lawyers tell us this is fraught with potential difficulties. One major question is whether accepting EU compensation would stop you suing successfully – flight delay solicitors Bott & Co say you wouldn't be able to proceed if you've accepted "full and final" compensation, but it's not clear whether that would include compensation under EU rules.

Realistically, this probably isn't something to attempt without legal help, and even then you'd need to weigh up carefully if it's worth it.

What if I had to book replacement flights with another airline?

Some passengers were unable to wait for an alternative flight and had to make their own arrangements. For example, former MSE senior news reporter Callum Brodie told us his flight from Faro, in Portugal, to Heathrow was cancelled and he ended up paying almost £500 to fly Easyjet to Gatwick instead.

It's worth noting though that some passengers – including Callum – say they were told by BA staff they would also be able to claim the cost of rebooking themselves onto alternative flights.

BA had initially said it would look at claims like this on a case-by-case basis to see if these passengers can reclaim the extra cost. It has now updated its website to says passengers who had to book alternative flights because BA could not re-route them ARE eligible to make a claim.

If you're in this situation and considering booking your own replacement flights, always try to get any promises from staff in writing.

What if I missed a connecting flight?

If you were unable to make a connecting flight because of the BA problems and it was all booked on the same ticket, the airline should refund you the whole ticket price. What matters for the purposes of the EU compensation rules is the time you arrive at your final destination.

But if you booked your connecting flight separately to your original flight, and it was on a separate ticket, you're only entitled to claim under EU rules for the flight you actually missed – though it's definitely worth complaining to BA anyway. You could also check with the airline you were due to fly with to see if it can help.

What if my bags were delayed?

If your bag was delayed and you had to purchase essential items, you can file a compensation claim using your receipts.

It could also be worth checking your travel insurance. The Association of British Insurers (ABI) says many policies will cover you for the essential items you need while you wait for your luggage, up to a certain amount (this is really if you're stuck away from home). For example, Aviva travel insurance has baggage delay cover up to £300, while Direct Line cover varies from £100 to £1,000. Although the ABI says it's unlikely policies will cover you for consequential loss resulting from baggage delay.

If your insurer does cover you, you'll need to weigh up whether you should claim from your insurer or BA. You won't be able to claim from both, and remember there's usually an excess you'll have to pay on an insurance claim.

BA: 'We're extremely sorry'

BA says the problems resulted from a massive crash of its global IT system, which it says was due to a "power supply issue". It says there's no evidence the problems were the result of any kind of cyber-attack.

A spokesperson said: "We are extremely sorry for the frustration and inconvenience customers experienced over the bank holiday weekend and thank them for their patience and understanding.

"We have been providing customers with letters and information on how to apply for EU compensation and to claim for reasonable expenses. We will fully honour our obligations."