The airport parking change that's catching Britons out - and landing them £100 fines

 Birmingham, Gatwick, Heathrow, Luton, Manchester and Stansted are among the airports now using automatic number plate recognition to track how long you park for and how much you owe.

That means there are no barriers prompting you to pay - meaning you'll have to remember to pay online or by phone, with the deadline being midnight the following day in most airports.

If you don't pay on time, you'll get a parking charge that could range from £80 to £100 - though it is reduced if paid in 14 days.

Are the fines legal?

The legal basis for these fines has been challenged.

Which? has highlighted the case of a barrister who challenged the legality of Heathrow's £5 drop-off charge and avoided a fine for non-payment.

Edward Levey, a King's Counsel at a London chambers, didn't pay Heathrow's new £5 fee when dropping off his daughter at the end of last year. The following night, he realised he'd forgotten to pay and this meant he was threatened with an £80 fine, reduced to £40 if he paid within 14 days.

He admitted there were many signs at the airport warning of the drop-off charge, but believed that - because it's difficult to pay in the moment - many people will forget as soon as they get home.

He attempted to appeal against the fine but parking firm APCOA, which runs the system for Heathrow, turned down his appeal and appointed a debt agency to recover the money.

The parking firm dropped the fine before the challenge went to court.

If you're considering an appeal, Which? says you should start by doing so via the operator that issued the parking charge.

If that appeal is rejected by the operator, you should contact Parking on Private Land Appeals (POPLA) within 28 days of the rejection notification.

POPLA is a free, independent appeals service available across the UK.

Before arriving at some airports, you can register for an autopay account, which automatically charges your card - but you should always check how much you've been charged at any barrierless car park.