Energy regulator Ofgem launched an investigation on Tuesday into Scottish Power Limited and Scottish and Southern Energy Plc. The investigation is being launched under section 18 of the Competition Act 1998 (the Chapter II prohibition) and Article 82 of the EC Treaty.

Ofgem said that it had decided to begin the investigation following a formal complaint alleging abuse of a dominant position in the electricity generation sector arising from constrained capacity on the transmission network. Ofgem said it had also received informal enquiries.

Ofgem noted that the investigation was separate from a probe launched in February relating to energy supply markets.