A watchdog is advising holidaymakers against booking with 20 package holiday providers because of “shortcomings” with refund commitments due to Covid-related disruption.

Which? said its “red list” of companies that could leave customers out of pocket if they are unable to travel as planned included major operators Lastminute.com, Love Holidays, On The Beach and Teletext.

Companies that did not provide clear information on their booking policies were also rated as red for a lack of transparency.

The consumer group said the policies of operators on the red list were not necessarily in breach of consumer law, although some have faced investigations by the Competition and Markets Authority (CMA) in the past year over failures to refund their customers, such as Love Holidays and Teletext.

Which? is advising anyone considering a holiday to avoid booking with a “red” company, and to check before they book to ensure their provider offers a good flexible booking policy.

The best companies won’t leave you high and dry

Which? considered each company’s various policies on coronavirus-related disruption, including whether it would refund customers in the event of a lockdown, if Foreign Office advice changes, or if customers are forced to quarantine in a hotel on their return.

Companies that committed to offering refunds in most scenarios put to them by Which? included British Airways Holidays, First Choice, Hays Travel, Jet2 Holidays, Trailfinders and Tui.

Which? also asked companies if they would provide full refunds in the event someone is told to self-isolate before they travel, following the rise in the number of people being contacted by NHS Test and Trace, and found only three companies – Exodus, Explore and Discover Egypt – guaranteed refunds in this situation, as well as every other scenario put to them.

The watchdog said it would regularly evaluate providers and update its lists accordingly.

Which? Travel editor Rory Boland said: “Between changing travel restrictions, both in the UK and abroad, and the ongoing risk of being told to self-isolate, booking a foreign trip still comes with some uncertainty and things can go wrong if you’ve chosen the wrong provider.

“The best companies won’t leave you high and dry though, so it’s vital to do your research before booking.

“The difference between choosing a red company over a green company could be losing the entire cost of your holiday if circumstances change and you have to amend or cancel your plans.”

On the Beach said: “If the FCDO advises against travel to a destination, our customers can change their holiday destination or dates free of charge, and we will waive any of our admin fees.

“If they wish to cancel their holiday, we will fully refund hotel and transfer costs, and our regulated, ring-fenced trust account means that we are able to do this quickly and always in cash rather than credit notes or vouchers.

“Our holidays include flights from multiple third party airlines and the decision on whether to operate those flights lies with each airline.

“If the airline cancels the flight, then we will, of course, pass the refund straight on to our customers in full.

“If a customer wishes to cancel their holiday due to FCDO advice, but the flight operates as planned, the airline retains the monies paid for the flight, and in those instances this leaves us unable to pass a refund on to our customers.”

Holidaymakers can check their provider against the lists online via the Which? Holiday Checker.