The company - a British subsidiary of French firm EDF - is one of the country's largest energy suppliers and will be a "tier one" sponsor of the Games.

EDF will have exclusive marketing rights in the utility services sector for the London Olympics.

It is believed they paid £50 million to secure the sponsorship.

"We're looking forward to working with EDF to make London 2012 a truly sustainable Games, delivering a lasting legacy benefiting sport, the environment and the local and global community," London 2012 chairman Sebastian Coe said.

"This is a continued declaration of support from the commercial sector.

"[LOCOG] raises all its money from the private sector, we don't have the Lottery or tax to fall back on.

"These guys (tier one sponsors), particularly EDF today, are partners, not just sponsors, and will help us deliver a better Games because they bring expertise to the table which is absolutely essential to our vision.

"We want to leave something that lasts and EDF understood right from the start that it was not about just pitching for 16 days of sport.

"It's about changing landscapes, inclusivity, biodiversity, healthy living, climate change, this why EDF is such an important partner for us."

In March, London organizers signed up their first tier one sponsor, bank Lloyds TSB in a deal worth £80 million.

EDF chairman and chief executive officer Pierre Gadonneix said his company was Europe's lowest carbon-emitting energy supplier.

"With these Olympic and Paralympic Games, we want to deliver the vision of inspiring future generations and leaving a lasting legacy, in sport and in society," he said.