Workers at one of Britain’s “big six” private energy companies could face huge job losses through a restructuring exercise, general union GMB warned yesterday.

Eon, which is part of a German transnational corporation, has announced plans to split the company in two with the formation of a new company to look at alternative energy sources.

Eon chief executive Johannes Teyssen said the company was responding to “dramatically altered global energy markets, technical innovation, and more diverse customer expectations.”

He said two separate companies were needed, one of which will deal with new sources of energy.

GMB energy secretary Gary Smith said “huge forces now at play in the energy sector globally and in the UK” were behind the “radical” shake-up of Eon’s structure.

“GMB is anticipating radical restructuring of the sector over the next few years and large job losses. There is no doubt that there will be casualties as a result of this restructuring.

“The decline in the price of oil will most likely speed up the fall in employment in the North Sea. The electricity markets review and competitions inquiry in the energy sector will also drive a greater shake up in the UK energy market. The next few years are going to be difficult and tough for everyone in the energy sector.”

In May energy regulator Ofgem ordered Eon to pay 330,000 customers £12 million due to its poor sales practices.