Consumer group Which? said the number of consumers seeking its advice on so-called chargeback applications to debit and credit card providers had risen tenfold to 10,000 in March and April compared with the two previous months.

The chargeback process - offered by most card providers - reverses a transaction if a customer is unable to resolve a dispute with a business for a variety of reasons.

Which? said that huge numbers of unhappy consumers were hoping to take advantage of this option after coronavirus lockdowns forced the cancellation of thousands of holidays, flights and events worldwide.

But some lenders have been accused of rejecting claims because customers had been offered credit notes or vouchers to rebook cancelled trips and services at a later date.

Customers making refund claims under Section 75 of the Consumer Credit Act 1974, a legal protection for credit card users on purchases of between 100 pounds and 30,000 pounds, were also being told that applications would be handled case by case, Which? said.

To tackle confusion over the protections offered, Which? called on banks to be more transparent on the types of chargeback and Section 75 claims that are likely to be successful in relation to coronavirus-related cancellations.

"There needs to be greater clarity and consistency about claiming through banks, and the industry should ensure that all bank customers have a fair chance of getting their money back," said Gareth Shaw at Which?      

A spokesman for banking trade body UK Finance said that paying with a credit or debit card can provide customers with additional protection if something goes wrong, but circumstances under which a refund can be made can be complicated.

"We would always advise customers who are unable to resolve a complaint with the retailer, and have paid using their credit or debit card, to check with their bank, building society or card issuer," the spokesman said.

By Sinead Cruise