The British Government says shops in airports must cut their prices after accusing retailers of failing to pass on VAT discounts to passengers.

The intervention comes after it was reported that some major retailers are not passing on the VAT relief they get to customers.

UK Treasury minister David Gauke said stores should not being using the discount to boost their profits.

"The VAT relief at airports is intended to reduce prices for travellers, not as a windfall gain for shops," he said.

"While many retailers do pass this saving on to customers, it is disappointing that some are choosing not to."

"We urge all airside retailers to use this relief for the benefit of their customers."

Steve Baker, a Conservative member of the Treasury select committee, told the Daily Telegraph that passengers were being "ripped off".

"Consumers are entitled to expect that tax savings will be passed to them rather than become another addition to the bottom line for companies," he said.

"I always thought that showing a boarding pass was an official requirement."

Many airport stores ask passengers to present their boarding cards when making a purchase.

The information on the boarding cards can then be used to claim VAT relief on sales to people leaving the EU.

The relief means retailers do not have to pay the 20% VAT on the goods they sell to those passengers.

It is not a legal requirement for passengers to show their boarding cards when buying goods at airports.

When Boots were contacted for a comment, they said: "Our airport store teams are asked to request and scan boarding cards to ensure the accuracy of our accounting records, which includes the accurate reporting of VAT."

"Our pricing in airport stores is consistent with our London prices and VAT is not taken into account when setting prices of products."

"Showing a boarding card is not a compulsory requirement and any of our customers that do not wish to share this information can shop with us without the boarding card being scanned."