The UK Treasury has called on airport stores to pass on the discounts to customers who are travelling outside the European Union.
Passengers across the UK airports are refusing to display their boarding passes while purchasing goods at airport shops after the Independent revealed that the information is being used by retailers to avoid 20% VAT on such customers' purchases.
The VAT relief at airports is aimed at reducing the prices of products for customers.
UK Treasury financial secretary David 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."
Various polls revealed that most travellers were unaware of the fact that they were not required to show their passes, with many thinking they were legally required to do so, reported Yahoo News.
Airports including London's Heathrow witnessed protests at the branches of WHSmith and Boots.
A Boots spokesperson was quoted by BBC as saying that while they claimed some of the VAT for non-EU passengers, they did so in accordance with the government's rules.
WHSmith said that it would be difficult to have a pricing system that would differentiate between people travelling to EU and non-EU destinations.
According to The Independent, some airport shops are also making profits of up to 100% on each alcohol sale they make to passengers leaving Europe.