Under the government’s smart metering implementation programme, suppliers are required by their licences to take all reasonable steps to roll out smart meters to all homes and small businesses by 30 June 2021.

To work towards this, suppliers set their annual targets for smart meter installations and Ofgem monitors performance against these targets on an annual basis.

Ofgem said the opening of the investigation does not imply that it has made any findings of non-compliance by Scottish Power.