British Gas is an energy and home services provider in the United Kingdom. It is the trading name of British Gas Trading Limited, British Gas Services Limited, British Gas Services (Commercial) Limited, British Gas New Heating Limited and British Gas Insurance Limited, all of which are subsidiaries of Centrica. Serving around ten million homes in the United Kingdom, British Gas was the largest electricity supplier in the country until 2024 when it was overtaken by Octopus Energy. It remains the largest gas supplier. It is considered one of the Big Six dominating the gas and electricity market in the United Kingdom.