also coke, which was sold off as the by-product of gas-making. Ammoniacal liquor, another by-product, was mixed with sulphuric acid, dried and ground to make a powder which was sold as an agricultural fertiliser. The clinker from the retort house was sold to a firm in London to be used as purifier beds in the construction of sewage works. Salisbury power station supplied electricity to Salisbury and the surrounding area from 1898 to 1970. The power station was at Town Mill and was owned and operated by Salisbury Electric Light and Supply Company Limited prior to the nationalisation of the British electricity supply industry in 1948. The coal-fired power station was redeveloped several times to incorporate new plant including a water driven turbine. From the Middle Ages to the start of the 20th century, Salisbury was noted for its cutlery industry. Early motor cars were manufactured in the city from 1902 by Dean and Burden Brothers, using the Scout Motors brand. In 1907 the company moved to a larger factory at Churchfields; each car took six to eight weeks to build, mostly using bodies made elsewhere by coachbuilders. By 1912, 150 men were employed and the company was also making small commercial vehicles and 20-seater buses, some of which were later used by the newly established Wilts & Dorset operator. The Scout company failed in 1921 after wartime disruption and competition from larger makers. Shopping centres include The Old George Mall, The Maltings, Winchester Street, and the Crosskeys precinct. Major employers include Salisbury District Hospital. Closure of the Friends Life office, the second largest employer, was announced in 2015. Culture Salisbury was an important centre for music in the 18th century. The grammarian James Harris, a friend of Handel, directed concerts at the Assembly Rooms for almost 50 years up to his death in 1780. Many of the most famous musicians and singers of the day performed there. Salisbury holds an annual St George's Day pageant, the origins of which are claimed to go back to the 13th century. Salisbury has a strong artistic community, with galleries situated in the city centre, including one in the public library. In the 18th century, John Constable made a number of celebrated landscape paintings featuring the cathedral's spire and the surrounding countryside. Salisbury's annual International Arts Festival, started in 1973, and held in late May to early June, provides a programme of theatre,