Throughout the second half of the twentieth century, Alfred McAlpine was a major road builder, being responsible for the construction of over 10% of Britain's motorways, including the M6 Toll (as part of the CAMBBA consortium).

Under a non-compete agreement with its former parent company, Sir Alfred McAlpine confined itself to civil engineering and to the north west of England.

During 1958, the company was floated on the London Stock Exchange under the name Marchwiel Holdings, changing its public name to Alfred McAlpine PLC only in 1985.

[4] This move came two years after the decision to end the non-compete agreement with Robert McAlpine, allowing the firm to expand geographically.

[10] In 1991, Bobby brought in an outside chief executive and resigned as chairman one year later, by which time the family no longer owned a controlling shareholding in the business.

[9][11] During the mid 1990s, rival British construction firm Amec Foster Wheeler made an all-share offer to merge with Alfred McAlpine; however, the latter's board voted against the move.

[17][18] In May 2006, Alfred McAlpine commenced its largest ever facilities and building management services contract for Mapeley's entire UK property portfolio; by this point, 75 percent of the company's activities was in the private sector.

[19] During February 2007, the company took a £13m hit after serious accounting irregularities were discovered that were later attributed to the deliberate collusion of several managers at its slate business across multiple years.