Telecoms giant BT today said rising demand for broadband had helped it to its fastest underlying revenues growth in nearly three years.

BT said it was connecting a new broadband customer every 15 seconds as turnover from "new-wave" services broke through the £1 billion mark in the second quarter.

High-speed technology now accounts for 22% of group revenues as BT stepped up its transition from a fixed-line operator.

A record 607,000 customers were hooked up to broadband in the three months to September 30, boosting its total end user base to 3.3 million.

BT said pre-tax profits for the quarter were 4% higher than a year ago at £549 million, with underlying turnover up 2% at £4.6 billion.

Chief executive Ben Verwaayen said: "We are winning business across the globe and responding innovatively to an intense competitive environment, particularly in the UK."

BT blamed a 6% fall in its traditional fixed-line business on competition, price cuts and measures to encourage people to sign up for broadband.

At the same time, the group saw revenues eroded by a cut in termination rates - the price that mobile firms charge each other and landline operators for putting calls through to their customers.

Today's results come just days after BT announced the £520 million acquisition of California-based Infonet, which supplies internal communications systems.

The deal was given a lukewarm response on Monday by investors who recall the £1.2 billion hit from unwinding BT's loss-making US joint venture with AT&T in 2001.

Mr Verwaayen described the deal as "another step in BT's transformation into a leading provider of IT and networking services".

BT disappointed investors in July with its first-quarter numbers and today said interim profits were 4% lower than a year ago at £983 million. Half-year turnover was flat at £9.2 billion after accounting for the cut in termination rates.

BT said the cost of supporting its push into the market for high-speed technology had put margins under pressure. Operating margins were 0.4% lower in the second quarter compared with the same stage of 2003.

Turnover from corporate customers rose 2% and high-speed technology now accounts for nearly half the sales to this sector.

Moves to adopt a simpler pricing structure to defend its traditional business were also having some success, with 8.7 million customers signing up for BT Together since July 1.

This month should see the first results of a review by regulator Ofcom, which is considering a break-up of the company as part of a strategic review of the telecoms sector. Analysts believe this review is likely to overshadow today's figures.