Apax Partners, the private equity group, has led a £15m second-stage funding in Nexagent, the telecommunications venture founded by Charlie Muirhead, one of Britain 's youngest technology entrepreneurs.

The investment will see Mike Grabiner, a former chief executive of Energis and a director at Apax, join the board of Nexagent, making this the first board of an investee company that Mr Grabiner has joined since becoming a director at Apax.

This latest cash injection takes Nexagent's funding to £28.2m and will be used to complete the global roll out of its interconnect points designed to link together the networks of competing telecoms operators.

Nexagent is seeking to simplify global telecoms solutions for leading enterprises by joining together the networks of different operators and then managing and monitoring telecoms services on behalf of companies.

"Nexagent is introducing a disruptive technology," Mr Grabiner said. "It solves a major pain point for a lot of enterprises."

Mr Muirhead first came to prominence after setting up Orchestream, a software provider, after having left university at 21.

Orchestream was sold this year to MetaSolv, a US rival, for £7.9m, having reached a valuation of almost £1bn at the height of the technology boom.

Mr Muirhead stepped down as chief executive of Nexagent this year and handed the reins to Royce Murphy, a former chief executive of PeopleDoc, a start-up software developer.

Mr Muirhead said Nexagent was in talks with at least one large enterprise about supplying its global telecoms service requirements.

Nexagent is expected to announce its first important customer win in the early part of 2004. Other investors include Atlas Venture, Benchmark Capital, Quester Capital and Lago Ventures.