Airline watchdog the CAA has revealed that it was investigating Goldtrail Travel in the weeks leading up to the collapse of the UK’s largest independent tour operator. Forensic accountants have now been enlisted to investigate the accounts.

More than 16,000 British passengers were left stranded abroad when Surrey-based Goldtrail was put into administration in July.

According to liquidation documents in May the company was “subjected to an investigation by the Civil Aviation Authority (CAA) in which the company’s policies for invoicing and APC [customer protection payments] were reviewed”.

According to The Telegraph, the CAA then demanded a bond worth 10-15 percent of the company’s turnover - around £8m - which Goldtrail was unable to pay.

Its former owner, Kadir Aydin, claims that the CAA inquiry contributed to the company’s collapse because this “distracted [executives] from their managerial responsibilities”.

The company’s administrator, Begbies Traynor, in conjunction with the CAA, have now appointed forensic accountants from PricewaterhouseCoopers to conduct deeper investigations.

“In order to avoid any prejudice to potential actions, no further details pertaining to the investigations will be divulged at this time,” said the administrator.

Goldtrail’s collapse is expected to cost the CAA’s Air Travel Trust Fund up to £20m in compensation claims from customer.

Document reveals that the tour operator owed £5.7m, including £150,000 to HMRC, plus numerous smaller amounts to many thousands of small hotels in Turkey and Greece, and more than £1.5m to two airlines, Turkuaz Airlines and Onur Air.