Ofgem this week announced Scottish and Southern Electricity will be investigated after a complaint alleging abuse of a dominant position in the electricity generation sector.

It is also investigating Scottish Power, which is owned by Spain’s Iberdrola.

Scottish and Southern Energy (SSE) is one of the largest energy companies in the UK, trading as Southern Electric, Scottish Hydro Electric and Swalec.

It is involved in the generation, transmission, distribution and supply of electricity, as well as energy trading, storage, distribution and supply of gas, electrical and utility contracting and telecoms.

A spokesman for SSE said on Tuesday: “No specific allegations have yet been put to SSE, but we are confident that our actions in the electricity generation market have always been justifiable in economic terms and consistent with the operation of a competitive market.

“With any Competition Act investigation there is a process to be followed and we will co-operate fully with Ofgem throughout this process in order to bring it to a speedy conclusion.”