Star of last night's sale was Concetto Spaziale of 1961 by Lucio Fontana inspired by the shape of the city of Venice; it sold very slowly for £4,409,250, shy of its estimate between £6 million and £8 million. Behind it was Jeff Koons's Stacked, a painted wood mountain of two dogs, a goat, a tit and a fat pig from his Banality series of the Eighties. Its £2,841,250 price was on estimate but the estimate was a wintry one; it announced a fall of around £1 million in value from last summer for the world's most expensive living artist after Lucian Freud.