Shares of the Nasdaq-quoted company rose 17.97% to $28.75 when it acknowledged the approach, though it said it had not engaged in negotiations with the company making the offer and the bid will be withdrawn if the terms are disclosed.

Virgin Media, which has more than 15 million subscribers, was formed by the merger of cable operators NTL and Telewest. It acquired a new identity in April 2006 when it paid 962m pounds ($1.69bn) for wireless carrier Virgin Mobile to become a quad-play operator offering mobile phone, fixed-line, pay TV, and internet access.