BT has launched an aggressive attack against cable operators, introducing the UK's first large-scale deployment of Voice over Internet Protocol (VoIP) solutions.

The company's Broadband Voice package offers a consumer service that's custom-built for cable broadband users.

Using an adaptor that connects the phone and cable line, customers can simply plug into the service, with no need to reconnect their line to BT.

The company is deliberately launching the service in areas specifically served by Telewest and NTL customers. It's a war for market share. BT Retail chief executive Pierre Danon said: "Broadband Voice takes the battle for customers right to the door of our rivals. This offer combines innovation and value-for-money and will offer cable customers an alternative voice line from BT for the first time, and provide them with potential savings of up to £109 a year on their phone calls."

BT claims the service lets users save up to 57 per cent on calls to mobiles and up to 25 per cent on UK daytime calls.

The claimed money-saving service from BT costs £7.50 per month.