Lord Turner of Ecchinswell is preparing to step down from his second job as the Government’s top adviser on climate change to focus on plans for a sweeping overhaul of City regulation.

The chairman of the Financial Services Authority said that the economic crisis had left him unable to cope with the additional workload of being chair of the Committee on Climate Change.

“It is just too much for one man,” he said, speaking on the sidelines of the World Economic Forum in Davos. “It would still have been possible if we were in normal times.”

Lord Turner was appointed as FSA chairman in May 2008 and took up the role in September, just weeks before the collapse of Lehman Brothers sent shockwaves through the global financial system.

He said the FSA post was meant to have been a three to three-and-a-half day a week commitment, whereas his previous role on the climate change committee was meant to have taken up just one day a week.

“Since September the job of being FSA chair has been a seven-day-a-week job and it continues to be that,” he said.

Lord Turner said that his schedule had become increasingly unworkable as he has played a key role overseeing the effective nationalisation of some of the country’s big high street banks including Royal Bank of Scotland and Bradford & Bingley.

The former Director-General of the CBI said a new committee chairman would be appointed in due course, although he would remain a member of it. The Committee on Climate Change is an independent body that advises the Government on setting and meeting carbon budgets and emissions targets.

It reports to the Department for Energy and Climate Change and published a report in December laying out a detailed plan for how the United Kingdom could reduce its emissions of carbon dioxide by as much as 80 per cent by 2050.

Following his appointment, the FSA did not disclose Lord Turner’s salary but his remuneration is likely to be similar to the £433,000 earned in 2007 by his predecessor. Lord Turner had earlier worked as a director of Standard Chartered Bank and was vice-chairman of Merrill Lynch Europe. Between 1992 and 1995, he was a director of McKinsey in Eastern Europe and Russia.