Telewest is now known as Virgin Media.
You need a cable modem (provided by Virgin Media) but in a non cable area they do have an ADSL service.
I am on their 20 Meg service and been on broadband since 2001 with Telewest and never had a problem. I would think most of their cabling is less than 20 years old.
You can have just the broadband. I do.
Stewart
May 2008