Consumer group Which? found some airlines and package travel providers are refusing to provide refunds, in a breach of their legal obligations to their customers, while others are providing vouchers or credit notes – which may prove to be worthless if holiday firms run into financial trouble.

Industry estimates suggest up to £7bn in payments made by UK customers are affected.

Which? contacted 10 of the UK’s biggest holiday companies, including TUI and Jet2, and 10 of the UK’s biggest airlines, and found that none are currently offering full refunds within the legal time frame. Some are refusing to provide refunds altogether and instead offering customers the choice of rebooking or accepting a voucher or credit note.

Under EU Denied Boarding Regulations, if you’re due to fly with an airline based in the UK or EU, or are flying from an airport in the UK or EU, you’re protected if your flight is cancelled, and should be refunded within seven days.

Frustrated customers told Which? how airlines are making it near impossible to contact them to find out if they will be refunded.

Richard Lartey, 27, from London, said he has been waiting over a month for his money to be returned for a cancelled BA flight.

Richard, who was due to fly to visit his pregnant partner in Austria, said: “The only option for a cash refund is to call up. Instead of holding customers in a queue the telephone system would simply hang up after playing a short message.”

BA has told Richard that his money will be returned, but he has yet to receive the money back.

Rory Boland, editor of Which? Travel, said: “We have been inundated with messages from desperate travellers, some who are thousands of pounds out of pocket as a result of cancellations and have no idea if or when they’ll see their money again.

“We do not want to see the industry suffer further as a result of this outbreak, but it cannot be on consumers to prop up airlines and travel firms, especially when so many will be in difficult financial situations of their own.

“The government must urgently set out how it will support travel firms and airlines to ensure they can meet their legal obligations to refund customers for cancelled travel plans – and avoid permanent damage to trust and confidence in the travel industry.”

Which? has created a 10-point plan for government, holiday and airline companies, and insurers, which it says will help maintain trust in the travel industry and protect holidaymakers.

The measures include: protecting consumers’ legal right to cash refunds, extending Foreign Office travel warnings to a definitive date, establishing a temporary government travel guarantee fund, and ensuring travel insurance terms and conditions are more transparent.