Business support services firm Mitie has become the second-largest manned guarding company in the UK after buying Rentokil Initial's security operations.
The £74.8 million price, part of a combined operation of more than 9,000 officers, includes £15.7 million debt.
Initial Security UK, the acquired business, has over 6,000 staff who provide guarding, aviation security, patrol and alarm response services to government, commercial, industrial and retail clients at over 2,000 sites.
The company made a pretax profit of £4.5 million on sales of £130.7 million in 2005.
In comparison, Mitie's existing security business generated turnover of £54 million in the year to March 2005.
In a separate statement, Rentokil, which first announced plans to sell its guarding division about a month ago, said it continued to explore the disposal of its manned guarding operations in North America and Belgium.
Mitie, which has 6,000 staff in the Midlands, said Initial Security UK complements its existing guarding arm with specialism in the aviation and retail sectors.
Mitie chief executive Ian Stewart said: "A new force in the manned guarding industry has been created.
"This acquisition transforms Mitie's security business, enhancing our strengths in terms of clients, sector specialisations and geographic footprint. There are exciting times ahead."
Mitie expects the acquisition to be earnings enhancing in the year to March 2007, but the full benefits of integration will not be felt until the following year.
Richard Moule, managing director of Initial Security UK, said: "I am delighted that we have become a part of Mitie.
"This is a positive move for the employees and customers. Mitie's strategic focus on the UK manned guarding market will produce significant opportunities."