Customers of Fasthosts are being advised to reset their passwords following an attack on one of its servers.

The internet service provider and web hosting company sent an email to its customers last week after fears hackers could have gained access to usernames and passwords.

It reads: "We are writing to inform you that we have recently discovered evidence of a network intrusion involving a Fasthosts server.

“We have reason to believe that the intruder has gained access to our internal systems, and that this may have in turn given them access to your username and some service passwords.”

The company claimed to have enlisted the help of security experts to fix the hole that the attacker used to gain control of the databases and has said it is working with police in an ongoing investigation.

However, as a “precaution”, Fasthosts is advising members to change their passwords which are used to access the main control panel, email, FTP and database services.

It has said these must be secure and not easily be guessed. They should also be a minimum of eight characters long and contain an upper case and a lower case letter as well as one number.

Customers who are concerned about their account are advised to call the company’s support team.