Question to the Department for Business, Energy and Industrial Strategy:

To ask the Secretary of State for Business, Energy and Industrial Strategy, what information his Department holds on the number of customers on the standard variable tariff of (a) British Gas, (b) EDF, (c) E.on, (d) Npower, (e) Scottish Power and (f) SSE; and what proportion of that company's customer base that number represents in each such case.

The Department collects tariff level data from energy suppliers in confidence and is therefore unable to publish this at an individual company level. Aggregate data is published online at: https://www.gov.uk/government/collections/quarterly-energy-prices. This shows that around 70% of domestic gas and electricity customers are on variable tariffs. These include standard variable and any tariff whereby the price is not fixed for a set period of time.