Carphone Warehouse yesterday unveiled a major push into the UK broadband internet market after posting a 36 per cent rise in half- year underlying profit.

The company, joining others by seeking to hitch the future of its telecoms services business to broadband internet, announced plans to unbundle up to 1,000 BT telephone exchanges.

The mobile phone retailer and telecoms provider said pretax profits were up to £37 million after an increase in connections and the opening of new stores.

Turnover was ahead 25 per cent at £1.29 billion in the 26 weeks to October 1 as Carphone opened 147 new shops but closed 22 older ones - taking its number of outlets to 1,711, including a number in the West Midlands.

Total connections grew 17 per cent to 3.2 million as subscriptions increased 21 per cent to 1.6 million and the number of pre-pay customers grew 16 per cent to 1.4 million.

Chief executive Charles Dunstone said: "We saw strong demand throughout the first half as incentives for customers continued to be compelling, with free handsets and half-price line rental deals widespread. The level of innovation and design currently being achieved by the leading handset manufacturers is creating a particularly attractive environment for customers."

The TalkTalk fixed-line service, which signed up its millionth customer in July, added a further 139,000 customers during the first half. The company has also just launched TalkTalk Mobile, which bundles fixed and mobile services.

Carphone said there would be a major push into the broadband market in 2006, with the company planning to unbundle up to 1,000 UK telephone exchanges.

This involves putting Carphone equipment into BT exchanges so it can control the line to the home and offer a range of telecoms services, such as phone lines and internet access.

Mr Dunstone said: "The outlook continues to be positive. We expect the mobile phone market to continue to grow year-onyear over the Christmas period and then into New Year."

He added: "Our strong commitment to the UK broadband market further builds on our foundations to become the clear number one alternative telecoms provider."