Users of Internet provider Virgin were flooded with hundreds of unsolicited emails in a matter of minutes last month, when the company sent thousands of messages to its customers but unwittingly allowed them to reply to the firm’s entire mailing list. Virgin currently has around five million subscribers.

The company said while this was a major problem, it only affected customers who bought their Internet service from Virgin.net. No similar issues were encountered by customers of its broadband and television services, the company said.

Virgin did not reveal the exact number of current and past customers affected by the emails, saying only that the number of its subscribers at present stands at 135,000.

The email issue evoked a flurry of online complaints by customers, with some claiming they received almost 250 messages and other users suggesting that setting up a filter would deal with the problem.

The Internet provider said in a statement that it is working to address the problem. Virgin added that while it is aware that emails are being continually sent out, only users with a Virgin.net email address are affected and only those sending a reply will reveal their email address. Cable service customers were not affected by the issue.

A small proportion of clients have received a message from one of the company’s suppliers but if they choose to ‘reply to all’, the message will be sent out to a large group of users, a spokesperson for Virgin said. The company advised people not to respond to such emails.