has agreed to buy Racal Telecom, a part of Britain's Racal Electronics PLC, for 1 billion, the companies said yesterday.

The acquisition is another big step for fast-growing Global Crossing, which owns and operates an advanced fibre-optic network in the United States.

Under terms of the deal, Global Crossing will pay 950 million in cash and assume Racal Telecom lease obligations worth 50 million.

The deal still must be approved by Racal shareholders and regulatory authorities.

Based at Bracknell, west of London, Racal Telecom operates fiber-optic telecommunications links between 2,000 towns and cities in the United Kingdom.

It represents "an exceptional opportunity'' that adds to Global Crossing's existing British operations and a pan-European network now being developed, said Bob Annunziata, chief executive of Global Crossing.

Annunziata estimated that the acquisition would yield net savings of about $450 million a year. No jobs are expected to be cut from among Racal Telecom's 1,300 employees, he said.

In clinching the deal, Global Crossing outbid Energis, a British telecommunications firm, which had earlier offered an estimated 800 million for Racal Telecom.

Global Crossing already plans to merger with US counterpart Frontier Corp., and it agreed in May to pay 550 million for the underwater cable-laying business of Britain's Cable and Wireless PLC.

Global Crossing offers the Racal business "a certain critical mass'' that is necessary for survival amid the rapid consolidation in the telecommunications industry, said Racal spokesman David Nicholas.

Racal shareholders would benefit from a reduction in company debt and a large cash payout, he said.

After selling its telecommunications network, Racal's business would consist mostly of defence and industrial electronics and transportation services.

Bob Annunziata, chief executive of Global Crossing