The news will come as a boost to the cash-strapped cable company which has been undergoing a financial restructure which is expected to emerge from Chapter 11 bankruptcy protection with its £12bn debt more than halved.
NTL's broadband subscribers are now twice those of rivals Telewest and BT, which each have around 250,000 - a slice of good news for the company which is haemorrhaging TV and telephony subscribers. It's latest third quarter financial results showed that customers had fallen by nearly 30,000.
According to NTL estimates, in homes with a choice between NTL broadband and BT's ADSL-based broadband services, about 80 per cent have chosen NTL broadband. Of the UK's total broadband user base, 60 per cent have selected broadband via cable modem.
NTL chief executive Barclay Knapp said: 'This is a remarkable achievement and testament to the quality of our broadband services.' NTL's on its network which now covers almost 50 per cent of the UK
The company currently charges customers £24.99 per month for a 600 Kilobit per second connection and £34.99 for a 1 Megabit per second service, both with free installation. Its basic 128kbps service costs 14.99 per month with a one off £75 installation charge or £50 for existing customers.