Mr Horler was previously the managing director of Powergen Retail, part of E.ON, and has held other senior executive positions in that group for more than 10 years. Prior to that, he was the sales and marketing director for ConocoPhillips in the UK and has worked in the US in that company’s supply and trading arm.

ScottishPower’s outgoing CEO, Jose del Valle, will be a member of the executive committee of the board. Iberdrola’s chairman and CEO, Ignacio Galan, will be the chairman of the newly-formed five-member executive committee, which will also include ScottishPower board members, Francisco Zuazo and Jose Alcolea.

Mr del Valle will maintain his dual role as strategy and development director at Iberdrola and director of group operations in both the UK and the US.

Under the new structure, the executive committee is appointed by and reports to the board of directors of ScottishPower, and will permanently operate as its representative. The committee will meet at least twice a month.