Bulldog Broadband has admitted that around 100,000 of its customers appear to have had private details stolen.

The customer contact details were "illegally obtained" by unnamed individuals in 2005, the company's former owner, Cable & Wireless, told The Guardian yesterday.

The stolen information is thought to include bank account and credit card details obtained via unsolicited phone calls to customers.

Cable & Wireless, which sold Bulldog's customer base to Pipex last year for £12m, uncovered the theft following an external enquiry.

A spokeswoman said that the number of customer records stolen was "in the region of 100,000".

"It's important to point at that we have absolutely no evidence that
 customers have had their credit card details used illegally,"she said.