In the UK, cable broadband is delivered via Virgin Media's fibre optic cable network. Speeds range from 2Mbps up to 200Mbps. Unlike ADSL broadband, cable broadband doesn't suffer from slower speeds the further away you are from the exchange which means you get the full broadband speed no matter where you are; this however does depend on what congestion there is at the exchange when using your internet.
Before Virgin Media there was NTL and Telewest, which merged with Virgin.net to form the Media branch.
Instead of using copper wires to transmit data, cable uses small bits of optical fiber to transfer information by light, far faster than the copper wire, and sometimes aluminium that BT use in its network.
Cable
