Joseph Percy Dean was the son of Chitterne farmers, Joseph and Louisa Dean. In 1902 he provided most of the capital of £3800 for a new venture with William and Albert Burden, previously clockmakers of Salisbury, to make motor engines. A new company was founded called Dean and Burden Brothers, motor engineers. Their premises were the Excelsior Works in the Friary, Salisbury, where clockmaking continued as well as the manufacture of motor boat and motor cycle engines. Percy Dean became a director of the company and their chief test driver.
In 1904 the company name was changed to Scout Motors and the following year their marine engines began to win accolades. Percy Dean took first, second and third places in races at Cowes, Ryde and Southampton Water in a 12 hp boat.
The first car was also produced in 1905. It was entered in the Isle of Man Tourist Trophy Race with Percy Dean driving, but it went off the road at Wallop on the way there and was unplaced. Despite this setback the firm was soon busy with orders and was notable as the only sizeable local industry. In Chitterne Polden and Feltham owned a Scout vehicle.
In 1906 Percy Dean was awarded an Automobile Club of Great Britain medal for coming 9th out of 26 starters at the Isle of Man Tourist Race. The factory in the Friary became too small and in 1907 the company moved to new premises built for them on the Bemerton Road at Churchfields.
Percy Dean drove the Scout car entered in the Isle of Man TT Race again in 1908 but the car ran out of petrol less than a 100 metres from the finish. The first Scout commercial vehicle, a motor delivery van, was produced in 1909 and production of marine engines stopped. For two years the company's sales increased, then in 1911 Percy Dean left to go to British Columbia. In his leaving speech he showed foresight when he mentioned the competition facing the company from foreign firms, for in 1921, having survived the hard times of World War I, the company was liquidated voluntarily.