Hackers have broken into the corporate databases for Best Western Hotels and may have stolen the names, addresses and credit card information of every customer who stayed with the international group since 2007.

An investigation by the Sunday Herald found that an unknown Indian hacker got into Best Western’s databases on Thursday and accessed its databases, which contain the names, addresses, credit card numbers and additional customer’s information of people who have used the chain internationally.

"Best Western took immediate action to disable the compromised log-in account in question. We are currently in the process of working with our credit card partners to ensure that all relevant procedural standards are met, and that the interests of our guests are protected," said a spokesman.

"We continue to investigate the root cause of the issue, including, but not limited to, the third-party website that has allegedly facilitated this illegal exchange of information."

The data on how to get into the database was apparently provided by an Eastern European hacking group and although the security hole the hacker used has now been closed the potential losses to customers could be huge.

It seems the hacker managed to insert a Trojan into the computers of a hotel and logged the user name and password of someone with sufficient security clearance to gain access to corporate servers.

The attack came to light after the company’s database was put up for sale on a sales board for such data.

"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. The Russian gangs who specialise in this kind of work will have been exploiting the information from the moment it became available late on Thursday night. In the wrong hands, there's enough data there to spark a major European crime wave."