Centrica plc is a British multinational energy and services company with its headquarters in Windsor, Berkshire, England. It is the largest supplier of gas to domestic customers in the United Kingdom, and one of the largest suppliers of electricity, operating under the trading names British Gas in England and Wales, Scottish Gas in Scotland, and Bord Gáis Energy in Ireland. Centrica is listed on the London Stock Exchange, and is a constituent of the FTSE 100 Index. Wikipedia