Thornycroft was established in 1859 by John Issac Thornycroft, a marine engineer. Thornycroft moved to marinise diesel engine for use in the marine market and in 1953 would have a selcetion of diesel engines ranging from 20Hp to 125Hp.
Thornycroft was a family run business until it became part of AEC / ACV Truck and Bus. Then, in 1962, Thornycrof twould be purchased by British Leyland where it would become the marine engineering division of the group.
In 1972 Thornycroft, now transferred to Beans Engineering, a subsidiary of British Leyland where it employeed over 1000 employees. The 1980's saw british Leyland break up and Beans Engineering, complete with Thornycrfot and Reliant Motors brands, was sold. Reliant Motors soon proved to be the downfall of Beans Engineering, and thus Thornycroft.
Thornycroft was sold off into private hands in 1995 where it continues to manufacturer marine engines and enjoys a worldwide reputation as a leading supplier of quality marine diesel engines and generators which are indivually marinised in the UK to ensure the highest quality and performance.
Some of the classic Thornycroft engines include the: