ERM, the environmental consultancy that advised on regeneration proposals for London’s successful 2012 Olympic bid, is to be sold by its venture capitalist owner for about £290m.

The owner, 3i, has appointed merchant bank Close Brothers to advise on the sale. The company is thought to have attracted interest from venture capitalist firms including ABN Amro Capital, Bridgepoint, Cinven, Electra Partners and Exponent.

It is understood that, in total, about 20 companies have submitted first-round offers for ERM, which will be cut to a shortlist of five or fewer bidders within the next two weeks.

The sale is expected to be finalised in September.