Support services group Amec has lost its UK chief executive, Carlos Riva, who has quit the company after less than two years.

A spokesperson for Amec refused to comment on Riva’s future plans, but a statement from the company said that he had left “to pursue his interests in energy sector development”.

As well as heading up the UK business, Riva was the chairman of Amec’s Americas business and was a member of the group’s board.

Amec has not replaced Riva, and the spokesperson said it was not yet certain whether it would do so in the future.

Lasse Petterson who previously reported to Riva, will run Amec’s Americas division.

In the UK, deputy chief executive Mike Straughen will continue in his role.

Petterson and Straughen will report directly to Amec’s group chief executive, Sir Peter Mason.

Mason said that Riva, who joined Amec in May 2003 from US power generation company Intergen, had departed on amicable terms.

Amec this week continued its push into the nuclear sector, with the purchase of French nuclear engineering company Game Nucleaire SAS for £14.3m. The French firm employs 620 staff and in 2004 reported a turnover of £32m.