Spirent, the Crawley-based electronics giant, is to buy US network services firm Hekimian for £1.1billion.

The company, which changed its name from Bowthorpe in March and was promoted to the FTSE-100 Index in September, is one of the world's largest suppliers of laboratory-based telecoms testing services.

Hekimian, based in Rockville, Maryland, helps firms deliver internet, voice and data services through telecoms networks.

Chief Executive of Spirent, Nicholas Brookes, said: "The exceptional strategic fit of Spirent Communications and Hekimian will enable us to provide leading-edge product and service assurance."

Under the terms of the deal, Spirent will pay £500 million in cash and approximately £605.6 million in new shares.

In the eight months to August 31, Hekimian generated profits before tax of £25.5 million and turnover of £91.1 million.

In September, Spirent announced pre-tax profits in the six months to June 30 of £32.7 million on a turnover of £316.4 million.

Chief executive and president of Hekimian, Des Wilson, said: "Spirent will enable us to develop our business and the complementary technologies will accelerate delivery of an exciting new generation of service assurance solutions."

The deal will be put to shareholders at an extraordinary general meeting on December 8.