Major retailers at Dublin and other airports throughout the country may have been defrauding customers and the government for years.

If you have ever been asked to present your boarding pass outside the Duty Free section of the airport you may have been deliberately overcharged. This has been a common ploy of major retailers for years a new investigation has revealed.

You are required to present your boarding pass at Duty Free to prove you qualify for the discounts. However many of the other retailers also ask you for your pass and the reason is more nefarious.

Travellers going outside the EU are entitled to have the VAT removed from the price of goods. To qualify the store must record the travellers flight and boarding details. However it has emerged that this discount is not always passed n and instead the stores are pocketing the VAT.

WH Smith has confirmed that scans are "a request, not a demand" at Dublin Airport.

"There is no obligation on the part of the customer," it said in a statement.

"VAT relief associated with the identification of customers travelling outside the EU is reflected in our single price and extensive promotional offers provided to all customers."

In other words they claim that a percentage of the VAT reduction is passed on to all customers, regardless of whether they qualify or not. And in turn this means that those customers who do qualify only receive a portion of the VAT rebate to which they are entitled.

Ireland's Competition and Consumer Protection Commission urged all retailers operating in Irish airports to be very clear with their customers as regards the circumstances where they collect VAT on behalf of the State or where VAT is not charged.

"Consumers should also be advised of the reasons why boarding cards are requested when making purchases in Irish airports," it added.