Four major airport parking comparison sites have changed their booking processes after a investigation found they were routinely charging for cancellation insurance and other extras unless you actively chose to opt out. If you're one of millions who've booked through Holiday Extras, BCP, Airparks or Looking4parking, you may be able to claim a refund.

Until a few days ago the comparison sites – some of which also sell other holiday services such as hotel rooms and airport lounge access – pre-ticked boxes at their online checkouts for additional services such as cancellation protection, SMS confirmation and charity donations. As a result, some travellers may have unknowingly paid more than they needed to when booking.

The amounts charged for the extras aren't exactly eye-watering – the largest individual charge we spotted with an airport parking booking was £1.69 – and overall booking via a comparison site is still usually much cheaper than booking direct.

But under consumer contract rules, a pre-ticked box does not usually mean consent has been given, so if you discover you've been charged in this manner it appears you'd have a decent case and you may be able to claw back your lost cash.

Since MoneySavingExpert contacted the comparison sites to question the charges, all four have stopped using the pre-ticked boxes online. While it's not clear exactly how many customers have been affected, at least four million bookings are understood to have been made with three of the sites over the past year.

Comparison sites can slash the cost of airport parking, and the savings from using one will usually far outweigh the cost of these extra 'pre-ticked' charges. See our Cheap Airport Parking guide for more details.

For example, we found parking for a week in July at Gatwick for £77 booking direct. Via Holiday Extras it was just £53 - even if you'd booked when boxes were pre-ticked and paid an extra £1.69 for insurance and 15p to charity, you'd still have saved around £22.

Yet while overall comparison sites are still a winner, it seems some sites have been adding extra charges by default, which may have led to some paying more for extras they didn't want. When we checked a number of other airport parking comparison sites, including SkyParkSecure, APH, FHR and Purple Parking, they didn't pre-tick any boxes.

What pre-ticked extras were comparison sites charging for?

Holiday Extras, BCP and Airparks charged up to £1.69 for cancellation protection with an airport parking booking, meaning you wouldn't have to pay a potential £10.50 fee if you had to cancel your booking, and 15p for a charity donation (extra charges when booking other travel services varied).

Looking4parking charged £1.49 for cancellation protection (against a possible £9.50 cancellation fee) and 49p for SMS booking confirmation.

How to check if you've been charged and demand a refund

To check if you've ended up paying for an extra you weren't aware of, look back at the invoice you were sent. Any extra charges such as cancellation protection, SMS booking confirmation or a charity donation should be clearly itemised there.

If you spot an extra charge, contact the company concerned to demand a refund, via one of the following methods:

All four companies have suggested they may refund customers who've unknowingly been charged.

  • Holiday Extras, BCP and Airparks (the latter two are run by Holiday Extras) initially told us they would immediately refund anyone who's unknowingly paid for an optional extra, though they've since appeared to backtrack and now say only that "customers who have any questions regarding the purchasing process can contact our customer services team".
  • Looking4parking has said it will refund customers who booked after clicking through from MoneySavingExpert and will refund others on a "case-by-case basis".

Yet even if a company claims you're not entitled to a refund, argue your case.

Under consumer rules, if you've been caught out by a pre-ticked charge you usually have a year and 14 days from your purchase date to contact the retailer and claim your money back. The company in question then has 14 days to refund you the full amount (see more on the rules below).

The Holiday Extras group hasn't confirmed how long it's been charging for pre-ticked extras or set a limit on how far back you can claim – so if you spot you've been unwittingly charged at any point, it's worth asking for a refund. Looking4parking reckons it started pre-ticking these boxes in May last year, so says it will only offer refunds for booking since then.

If one of the comparison sites refuses to give you a refund, a spokesperson for the Department for Business, Energy and Industrial Strategy told us you can report the firm to trading standards via Citizens Advice, or ultimately try and make a civil court claim. For more on this see the Small Claims Court guide - though given the sums involved are very low you'd need to think very hard about whether it was worth it.

Revealed: Millions charged by airport parking firms for  'pre-ticked' insurance and other extras unless they opt out
It's easy to miss these additional charges, so remember to be extra vigilant for pre-ticked boxes

When CAN'T you claim a refund?

You probably won't be able to get a refund for cancellation insurance if you've claimed on it, as you've used the service.

With SMS booking confirmation's it's more of a grey area, as strictly speaking by receiving the text you've used the service, but you may not have meant to opt in. Looking4parking has confirmed it will offer MSE users refunds for SMS booking confirmations as well as the cancellation waiver.

'It's vital sites act quickly to give a full refund'

Steve Nowottny, news and features editor at MoneySavingExpert, says: "It's deeply worrying that so many travellers booking through these sites appear to have been opted in by default to extras they simply may not have wanted. There's a real risk that a large number of travellers have been caught out and unwittingly charged.

"While it's good news that the sites have now stopped 'pre-ticking' these extras, that won't help anyone who's already paid. Anyone who's booked through these sites should check urgently if they've paid for insurance or other extras they never meant to buy – and if they have, it's vital these sites act quickly to give them a full refund."

What are the rules around pre-ticked boxes?

The rules around these are set out in the Consumer Contracts Regulations, which came into effect in June 2014 and apply when you're buying goods or services online or over the phone.

The implementation guidance states: "Traders will need the active consent of the consumer for all payments – pre-ticked boxes for additional payments, for instance, will no longer be permitted."

A spokesperson for the Department for Business, Energy and Industrial Strategy wouldn't comment on this specific case but told us if you've been unwittingly charged, you should "inform the retailer of the breach of regulation" and your "intention to withdraw from that contract, and request a refund of the additional charge".

Holiday Extras, BCP, Airparks and Looking4parking have told us they were unaware that pre-ticking boxes was against any regulation.

What do the comparison sites say?

Holiday Extras has removed the boxes across Holiday Extras, BCP and Airparks. A spokesperson says the pre-ticked box for cancellation insurance had been introduced "because of the level of complaints we got regarding cancellation charges".

"Since we introduced the pre-tick we have had only two complaints out of around four million customers," they added.

A spokesperson for Looking4parking says it had investigated the issue and had now unticked the boxes for all users.

If you've spotted any other companies or online retailers pre-ticking boxes at the checkout, email