Atkins chairman Mike Jeffries is to step down after 29 years at the firm.

Jeffries will leave the company on 1 January to be replaced by Ed Wallis, the 64-year-old former Powergen chief executive.

Jeffries, who is 60 next week, said that he was leaving the company with “mixed feelings”, and cited corporate governance as the reason. “I’m not retiring,” he said.

He said that he could not return as chairman in the future as he had once worked as chief executive of Atkins and would now be in breach of corporate regulations.

Jeffries has overseen many high-profile projects at Atkins, including the Burj al-Arab tower at the Jumeirah beach resort in Dubai.

He has also seen the firm through tough times. Two years ago, a profit warning caused shares to slide. “But in relative terms our shares have now recovered,” he said.

Jeffries will retain his position as chairman of client Wembley National Stadium Ltd.