The board's area of supply, encompassing 1,059 square miles (2,740 km2), included parts of the County of London, Berkshire, Buckinghamshire, Essex, Hertfordshire, Middlesex and Surrey.

[1] The board was responsible to the Minister of Fuel and Power, later the Secretary of State for Trade and Industry, for its operation and finances.

The board inherited a total of 1,746,200 consumers and 8,283 miles (13,330 km) of gas distribution mains.

The board concentrated production on those sites on the River Thames where coal could be delivered economically by its own fleet of colliers.

[4] In addition the board sold a range of other gas-making by-products such as tar, pitch, benzole, ammonia and other refined chemicals Although named North Thames, the gas board supplied gas to several areas south of the river Thames, including the Richmond, Morden, Chertsey, Ascot, Bracknell and Maidenhead areas.

The North Thames Gas Board operated staff sports clubs, welfare and other leisure activities for employees, inherited from its predecessor the GLCC.

The board was also responsible for the 1966 pilot scheme on Canvey to convert all domestic, commercial and industrial to natural gas.

[1] The technical transformation of gas manufacture and processing resulted in a significant reduction in the number of board employees, from about 25,000 in the 1950s to 8,000 in 1988.

[4] The war in the Middle East resulted in the closure of the Suez Canal, a 50 per cent increase in oil prices, and stoppage of gas import from Algeria.

The board's revenue account was in deficit by £4.3 million and there was a drive to cut costs and improve efficiency.

Central heating boilers and space heaters were promoted vigorously, and the arrival of natural gas enabled the board to offer attractive rates to industrial consumers.

The North Thames Gas Consultative Council was based at 28 Charing Cross Road.