Thomas Cook customers have been advised to be wary of unsolicited phone calls or emails about holiday refunds or cheap alternative trips.

UK Finance’s anti-fraud campaign, Take Five, Tweeted: “Criminals will use Thomas Cook going into liquidation as a cover story to scam you out of your money. Criminals will attempt to get individuals to disclose personal or financial information, which they will then use for their own fraudulent purposes.”

The Insolvency Service also warned Thomas Cook customers to be alert to scams, especially if they receive unsolicited contact from companies suggesting you re-book a Thomas Cook holiday through them.

The warnings came after several people took to Twitter to warn others about unsolicited phone calls they had received, purporting to be from Thomas Cook, ATOL or the customer’s bank.

For example, @czechgirllove Tweeted: “Thomas Cook refund agents just rang. If I would give my bank account details they will arrange immediate refund of my holiday. Only problem is I have not booked a Thomas Cook holiday. Some people will stop at nothing in their scam attempts.”

Thomas Cook went into liquidation on Monday after refinancing negotiations broke down. The Civil Aviation Authority is now running a repatriation mission to bring home about 150,000 holidaymakers currents overseas on Thomas Cook holidays.

About 21,000 employees of the group have lost their jobs, while the company’s shares are now worthless.

Tom Clementson, director at secure payments solution Shieldpay said: “Holidaymakers left stranded by the collapse of Thomas Cook are sitting ducks for fraudsters.

“Fraudsters who have absolutely no shame when it comes to parting people from their money and prey on those in vulnerable situations. Holidaymakers attempting to organise flights home, accommodation and compensation must be extremely vigilant. Unexpected phone calls with promises of compensation if bank details are provided are, in the vast majority of cases, too good to be true and people returning from holiday could see their bank accounts emptied before they step foot on home ground.

“Simple steps like never giving out bank details on the phone or clicking a link in an unexpected email should help people keep their money safe and avoid adding to holiday woes. Anyone who believes they have been targeted by fraudsters already should let their bank know immediately and report it to the police and Action Fraud.”