M&C Energy is being sold to a French energy management giant in a deal that values the Dunfermline-based consultancy at around £90 million.

Lyceum Capital, the London-based private equity business that bought the former McKinnon and Clarke in a £22m deal in 2009, said it has agreed to sell the company to Schneider Electric.

"Contracts have been exchanged and the deal ... is expected to complete in Q2 2012," said Lyceum Capital.

The terms have not been disclosed. It is understood that Schneider Electric has agreed to pay around £90m.

Lyceum bought a controlling stake in M&C to capitalise on growing demand for advice on energy matters.

Sandy McKinnon, a former military intelligence analyst who founded the company, had a stake of around 55%, with his family and associated trusts and funds, at the time of the sale. He retained a minority stake after the sale.

Mr McKinnon died in October last year.

M&C has acquired five complementary businesses in the UK and overseas since Lyceum bought it.

Dan Adler, partner at Lyceum, said M&C has been transformed into the largest outsourced energy management business in Europe.

Companies House filings suggest an employee benefits trust has a 4% stake in the entity that owns M&C, Mull Topco.

They suggest M&C's executive chairman Gerry Higgins has 6%.

A spokesman for M&C declined to comment on the sale.