Bonhams have declined to comment on reports in the media that the company is up for sale for a price rumoured to be several hundred million pounds.

Several potential buyers have been named, among them Formula One investor CVC Capital Partners and Bain Capital, the Boston-based private equity firm founded by former presidential candidate Mitt Romney, which has just announced that it has raised $935m for new venture capital projects.

At least two sources name boutique investment bank Greenhill as Bonhams advisors on the mooted sale.