Hammersmith Flyover is an elevated roadway in west London which carries the A4 arterial road over and to one side of the central Hammersmith gyratory system, and it links together the Cromwell Road extension (Talgarth Road) with the start of the Great West Road.
It was one of the first examples of an elevated road employing reinforced concrete balanced cantilever beam supports with a single central column. The deck spine and wings are of hollow prestressed concrete design. The flyover was designed by G. Maunsell & Partners, Consulting Engineers, led by Peter Wroth.
Construction was complete in 1961 and was carried out by Marples-Ridgeway, a Westminster-based civil engineering contracting company of which the then Conservative Transport Minister Ernest Marples had been a shareholder. To avoid a conflict of interest Marples undertook to sell his controlling shareholder interest in the company as soon as he became Minister of Transport in October 1959, although there was a purchaser's requirement that he buy back the shares after he ceased to hold office, at the price paid, should the purchaser so require.