Tourists who come to the UK from outside the EU to shop still have to apply for VAT refunds using paper forms.
Most other EU countries allow shoppers to apply for the refunds online.
But Britain has yet to implement a digital process five years after first outlining plans to modernise the tax-free shopping system – and has pushed back the delivery date to 2020.
Today 600 leading retailers clubbed together to warn the Chancellor that Britain is losing thousands of international tourist shoppers every year to European rivals.
They want him to speed up plans to modernise tax free shopping – pointing out that the Government’s failure to act threatens the £2.5billion value of retail sales that tax free shopping hands the UK economy every year.
The letter is signed by major department stores such as Harrods, shopping outlets like Bicester Village and groups such as the British Retail Consortium.
It points to research showing the Treasury would boost tax receipts by allowing shoppers to claim for refunds online.
Analysis by the Centre for Economics and Business Research shows there is a net benefit to the public purse of up to £1.90 for every £1 refunded with additional tax coming from greater visitor numbers and spending on other non-tax refundable goods and services, such as hotels, restaurants and transport.
The letter demands: “As a matter of urgency the government takes action to introduce a digital system at the earliest possible moment.
“We have lost confidence in HMRC’s ability to deliver its preferred option, which we believe is unnecessarily ambitious, will create an inferior product, will introduce additional risks and uncertainty, and will see the UK diverging from the global norms for tax free shopping schemes.