People have found out why they need their boarding passes to shop in airports and they’re not happy

You're actually only really required to show it at Duty Free

Anyone who’s ever woken up late, rushed to the airport and discovered they’ve forgotten the entirety of their make-up bag is familiar with shopping at airports.

Whether you’re picking up a can of essential dry shampoo, the best mascara boots has to offer or splurged £30 on a pair of flip-flops from Accessorize that you don't really want but definitely need, you'll know that the cashire always asks for your boarding pass. No-one questions it, we all just assume it's the done thing.

It turns out that the stores are actually using the information on our boarding passes to avoid paying VAT but are not passing on that discount to customers. So, no, it actually has nothing to do with security. (Although, for your own safety, this is why you should never Instagram your boarding pass).

According to an exposé by The Independent, stores like Boots are saving themselves 20 per cent VAT on goods being sold to customers travelling out of the EU despite keeping the product prices the same as on the UK high street.

Handing over your boarding pass to cashiers in airports is not a legal requirement, but many of these stores are clearly relying on passenger ignorance to continue pocketing millions of pounds in savings. Travellers have since expressed their anger and indignation at the scam and other airline secrets, with some customers having protested in stores at Heathrow Airport.

Refusing to hand over your boarding pass is the practical way to change the system, according to Money Saving Expert Martin Lewis.

'People withholding their boarding passes will force companies to take note and eventually take action,' he told The Independent.

Here's what you need to know...

When do I need to show my boarding pass in a shop?

You only need to show this when you're shopping in Duty Free. That's it.

Why are shops asking for my boarding pass?

Basically, if you're flying outside of Europe, the shop can then reclaim the VAT and they use your pass as proof. (Cheeky, we know).

So, next time you're asked for your pass, politely say no, and that's that.