Throughout the Second World War, the company worked on numerous contracts issued by the British government, including the construction of the Mulberry harbour units.

[1] The company undertook a variety of jobs across London throughout the mid-nineteenth century; early activities were centred around paving and roadworks at the behest of various local authorities.

The business was able to expand considerably towards the end of the century, permitting it to perform prestigious activities, such as its involvement in preparatory works at Westminster Abbey for the Diamond Jubilee of Queen Victoria in 1887.

[2] George Mowlem Burt, a civil engineer and grandson of George Burt, has been credited with successfully guiding the company through the construction of various large scale public works, including the Admiralty Arch and the Port of London Authority Building, as well as various maintenance contracts on behalf of the Office of Works, amongst others.

[4] During the Second World War, the company's reputation from its works during the interwar period led to it being awarded numerous contracts from the British government.

[5] Other wartime construction projects included the Royal Ordinance Factory Swynnerton as well as numerous tunnels and runways; the associated contracts were collectively valued at £29 million.

[1] During 1986, Mowlem acquired the scaffolding specialist SGB Group;[11] its purchase of Unit Construction that same year gave the company a substantial presence in the private house building sector.

However, a recession during the early 1990s led to Mowlem incurring losses in excess of £180m between 1991 and 1993, which placed pressure upon its banking covenants that compelled it to respond.

[17] During the mid-2000s, Mowlem entered into a period of financial difficulties; in 2005 alone, it issued four separate profit warnings and recorded losses totalling £73.4 million.

[18][23] The two companies were considered to be a good fit for one another, both having heavily involved themselves in various private finance initiative (PFI) schemes, taking on various responsibilities and functions traditionally performed by national governments.