During an investigation, the Scotland's Sunday Herald discovered that late on Thursday night a previously unknown Indian hacker successfully breached the IT defences of the Best Western Hotel group's online booking system and sold details of how to access it through an underground network operated by the Russian mafia.

The alleged hacker's name was not given in the report and it was also not mentioned how he was identified to be an Indian.

The cyber-attack reportedly scooped up the personal details of every single customer that has booked into one of Best Western's 1312 continental hotels since 2007.

Amounting to a complete identity-theft kit, the stolen data includes a range of private information including home addresses, telephone numbers, credit card details and place of employment.

"They've pulled off a masterstroke here," said security expert Jacques Erasmus, an ex-hacker who now works for the computer security firm Prevx.

"There are plenty of hacked company databases for sale online but the sheer volume and quality of the information that's been stolen in the Best Western raid makes this particularly rare.