Summer’s now over, and sadly there’s little you can do to repair a holiday ruined by flight delay or cancellation (eg from a strike like Ryanair’s) but many are entitled to up to £550 per person compensation. In fact this applies even for delays as far back as 2012.

This is not usually that difficult to do, I get positive feedback all the time, like Andy who tweeted me: “@MartinSLewis Quick thanks. Followed your advice. Just received 2 x £540 for flight delays Thomas Cook dealt with it very quickly too.” And Amanda: “@MartinSLewis Thank you. Put in a claim to EasyJet for a flight delay of 3 1/2 hours and have just received £703 compensation 10 days later”.

The easy rules apply to EU regulated flights.

This is all about EU regulation 261/2004 – and it’s important to mention that rule in any complaint you make as it has specific rules (and that’s due to move into UK law once we leave the EU).

This means you can claim a fixed amount of compensation if you meet certain criteria below, for flights going back to 2012. Here’s the key things to know…

1) It must be an ‘EU regulated flight’

That means the flight must have left from an EU airport (including all UK airports of course) or arrived at an EU airport (but in this case it must be an EU airline).

So a delayed Manchester to Miami flight qualifies, regardless of the airline. Yet for Miami to Manchester, you are entitled to compensation under this rule flying EU airlines like Virgin or KLM, but not on Air India.

2) It must have ARRIVED 3hrs+ late

It doesn’t matter how late you leave, it’s all about how late you arrived. So if you’re on a flight that takes off 4 hours late but arrives 2 hours 55minutes late – you’re not over the three hours needed to get compensation. And technically the time that counts is when the door opens to get off the plane.

3) It must have been the airline's fault to claim

So things such as bad weather, airport staff strikes or political problems doesn’t count, and you can’t claim compensation. However, things that are under the airlines control such as staffing problems, poor planning, and now even technical problems caused by not fixing regular wear and tear all count.

Airlines will try and play fast and loose with this – so listen carefully and note down what you’re told is the delay reason. If for example they’ve people working on the planes to fix them for hours but later claim bad weather – challenge it.

Ryanair has already declared it won’t pay compensation for the strike by some of its Irish pilots in July as it says it wasn’t at fault. Yet the regulator, the Civil Aviation, has said you should get it. So if it rejects you in the first instance just carry on to the next stage (see below).

4) You are entitled to cash

Airlines sometimes offer vouchers, so unless they’re offering more, you can formally say you want cash.

How do I put in a claim?

My full help including a totally free tool to do this is at www.mse.me/flightdelays. But if you want to do it manually, first, write to the airline stating the details of your delay and asking for the compensation.

If rejected, and that’s common, then depending on where you flew from and the airline you flew with, you can go to the relevant regulators for that country, or one of several new Alternative Dispute Resolution (ADR) schemes many airlines have signed up with.

If your appeal is unsuccessful it's still possible to go to court if you really want to press your case, though then you need to weigh up if it's worth it. And while I would always try and do this yourself for free up to this point – if you do decide to go to court then you may want to use someone like Bott & Co, a law firm that has been at the forefront of flight delay compensation, though it will take 25% of what you are due if you win as a fee.

How much compensation can I get?

The amount you get is fixed solely on the flight length and delay time. So a 1,000km flight delayed by three hours is €250 (£220ish) per person, while a 4,000km flight delayed for five hours is €600 (£540ish) per person.

What if my flight was cancelled?

Then you’re entitled to the choice of a refund or a replacement flight – and that applies whether it is the airlines fault or not.

However, if it was the airline's fault and it cancelled your flight within two weeks of departure, then you’re entitled to compensation on top if the arrival time of that flight is late. This is true even if you opt for a refund, as then you may still be due compensation if the alternative flight you were offered would have arrived later than your original flight.

Is this fair on the airlines?

I don't want to push unnecessary compensation culture. For someone on a £50 flight, only just three hours delayed, and had a fun time in the airport bar, it’s worth questioning whether it's fair to push for £220, after all, it could push up all our air fares.

Yet, if you’re a family with young kids who spent 24 hours in a smelly airport lounge with kids sleeping on the seats – then push for your rights. Everyone should make their own ethical choice of whether to take up the cudgels.

Martin Lewis is the Founder and Chair of MoneySavingExpert.com. To join the 13 million people who get his free Money Tips weekly email, go to www.moneysavingexpert.com/latesttip.