The deregulating movement in the early 90's led to the UK Electricity Supply Industry in England and Wales being privatised. The goal was to increase the affordability and dependability of the service by opening up the market to competition. Similar measures followed, leading to a fully deregulated market by 1998 and the commoditisation of electricity.
Now there are over 20 different gas and electricity suppliers in Britain offering a range of tariffs. The most predominate leaders of the market, known as the 'Big 6', are British Gas, EDF Energy, E.ON, Scottish and Southern Energy, Npower and ScottishPower.