1940s - Post-war nationalisation

The 1948 Gas Act is introduced. This creates a nationalised gas industry throughout England, Scotland and Wales, transforming the way the gas industry operates.

For over a hundred years, gas had been manufactured and supplied by a series of private and municipally operated companies. Under the Act, which came into effect in May 1949, over 1000 privately owned and municipal gas companies are merged into twelve area Gas Boards - each an autonomous body with its own chairman and board structure. The area boards became known simply as "the Gas Board", a term which is still often used when referring to British Gas.

The Gas Council is also set up to act as a link between the area boards and the Ministry of Fuel and Power, although the Council had no direct powers over the boards. The Gas Council is made up of the 12 area board chairmen and had a chairman of its own. Its first chairman was Sir Edgar Sylvester.

1950s - Growth of gas

The use of gas continues to grow and is promoted through high street showrooms. In 1953 the Women's Gas Federation is founded, providing a social forum for women where the use of gas in the home is further encouraged.

In 1959, the first trial imports of liquefied natural gas arrives in Britain from Louisiana. An Esso/Shell survey discovers an enormous natural gas field in Holland.

1960s - Gas consumption grows naturally

Technical advances herald widespread changes. In 1963, the Methane Princess and Methane Progress are brought into service to import liquefied natural gas from Algeria at the rate of 300,000 tons per year. A high pressure pipeline had been constructed to deliver this gas from the Canvey Island terminal as far as Leeds.

Surveys in the North Sea had indicated the enormous potential of tapping undersea reserves of natural gas. In 1966, the decision is taken to convert Britain to natural gas, and a year later the first North Sea gas is brought ashore at the Easington Terminal. During a ten-year national conversion programme every appliance in the country is converted from town gas to run on natural gas. Visits are made to 13 million homes and factories and 34 million individual appliances are converted.

1970s - Gas Boards go regional

The start of the decade sees the opening of a national control centre at Hinckley, Leicester, to manage the operation of the growing high-pressure distribution system.

The 1972 Gas Act paves the way for greater centralisation with the creation of the British Gas Corporation. Taking effect in 1973, the 12 old Gas Boards become regions, responsible for a particular geographical area.

Offshore exploration work continues, and in 1974 gas is discovered in Morecambe Bay. Commercial development of the field is given the go-ahead four years later.

In 1977 the national programme to convert to natural gas is completed.

1980s - Privatisation appears

Privatisation arrives with the 1982 Oil and Gas (Enterprise) Act giving the Government the power to dispose of British Gas's assets and open up the corporation's pipelines to third-party suppliers.

The 1986 Gas Act sees the return of the gas industry to the private sector and the company's name is changed to British Gas Plc. On 8th December 1986, £9 billion worth of shares were floated on the London stock market and sold around the world.

With the return of British Gas to the private sector, Ofgas is formed to regulate the industry and protect the interest of customers.

1990s - Greater competition introduced

In 1992, the market is opened up for industrial and commercial customers using between 2,500 and 25,000 therms of gas per annum. A range of alternative suppliers enter the market.

In the same year, British Gas undergoes a wide-ranging Monopolies and Mergers Commission (MMC) inquiry to balance the needs of customers, shareholders, suppliers and employees. When the MMC publishes its report in 1993, the Government decides instead to open domestic gas market to competition by 1996.

In parallel with this proposal, British Gas carries out a major restructuring to prepare the UK business for the onset of competition. Five business units are formed, each with a specific national responsibility:

• Public Gas Supply, the domestic market (now British Gas Trading).
• Contract Trading (later named Business Gas, for supplies over 2,500 therms a year)
• Transportation and Storage (later named Transco) responsible for transporting and storage of gas
• Service and Installation (later named Services)
• Retail (later named Energy Centres)

The Exploration and Production and Global Gas divisions continued to operate in international markets.

April 1996 sees gas competition opened up in Devon, Cornwall and part of Somerset. By the end of May 1998 the entire market is open to competition.

On 17 February 1997, following shareholder approval, British Gas plc is demerged into two separate companies:

Centrica plc

British Gas Energy Supply, Services, Energy Centres, Accord Energy and HRL (Morecambe gas field), The gas production business of the North and South Morecambe gas fields were transferred to Centrica plc.

BG plc

Transco (Transportation and storage business), International, Exploration and Production (excluding North and South Morecambe gas fields), Research & Technology and Properties.

In December 1999, BG plc completes a financial restructuring which resulted in the creation of a new parent company BG Group plc.

2000s - Extending the British Gas range of products and services

The range of products offered by British Gas in Great Britain is extended to include home security, plumbing, and kitchen appliance cover.

In September 2000, British Gas enters another new market with the launch of its telecommunications service.

Almost one year later in June 2001, British Gas extends its electrical servicing business into 80,000 more households across Britain with the acquisition of National Homecare.

British Gas Services now provides care for over four million heating and kitchen appliances.