An energy industry regulator described as a “thorn in the side” of the big six power supply companies has jumped ship to the private sector after Centrica reportedly offered to nearly double his salary.

Philip Davies was director of markets at Ofgem, the energy industry watchdog. He was among the most senior figures leading a drive for greater competition and lower barriers to entry in the UK power sector.

A spokesman for Ofgem said that Mr Davies left on February 6, two weeks before it announced an investigation into allegations of price collusion and anti-competitive behaviour in the power industry. Had Mr Davies stayed he would have played a lead role in the investigation.

Ofgem said that when Mr Davies told his superiors about Centrica's offer of a new role as director of regulatory affairs he was immediately placed on gardening leave. He is waiting to start the new position, while Ofgem has yet to find a replacement for him.

Industry sources believe that Centrica offered Mr Davies a basic salary of £150,000 to £200,000 plus a bonus. Ofgem declined to comment on how much remuneration he received in his former role. However, a similar director-level position is being advertised on Ofgem's website at “around £95,000 plus bonus”.

Mr Davies joined Ofgem in 2005 and headed the retail markets and environmental policy division until his appointment as director of markets in April 2007.

While at the regulator Mr Davies strove to make it easier for smaller companies to enter the energy supply market. Another aspect of his role was to end what the regulator considered sharp practices, such as the use of stringent tie-in contracts that give customers only a brief window of one month to switch suppliers without incurring penalties. Often the opportunity to move expired 90 days before the end of a supply agreement.

Before Mr Davies joined Ofgem he had worked at the Civil Aviation Authority and was director of regulatory affairs at Enron, the failed American power company. He also had stints at Aquila and Nuon.

Centrica said that it had appointed Mr Davies but declined to say when he would start or how much he would be paid. A spokesman said: “We need the best people we can find to handle all this and Philip has an excellent knowledge of regulatory affairs.”

A spokesman for Ofgem said that in his new role Mr Davies would have to operate under strict restrictions in accordance with rules set by the Cabinet Office.

Times Recommends

• Lies and cover-up at MG Rover exposed by report
• High oil prices push manufacturing costs up
• Primark founder steps down as chief executive