Airport shoppers are being encouraged to refuse to hand over their boarding pass at the Duty Free checkout.
This is after it emerged that many stores are using passengers' information to claim back tax.
The British government is urging airport shops to pass on VAT discounts to holidaymakers who travel outside the EU.
The Treasury says it's disappointed after it emerged many stores are adding the savings to their profits.
Founder of MoneySavingExpert.com, Martin Lewis, thinks collective pressure will help drive prices down:
"If they want my boarding pass, they're going to have to give me something in return. I would be perfectly happy if we split the difference, 10 percent for them, 10 percent discount for me. So this is what I say. If you're going to the airport this week, don't show your boarding pass, but do be prepared that they may refuse to serve you."
