Forget Bacon or Van Dyck this tiny stamp will make collectors go wild

A £12m stamp shows that modern collectors are driven by the same obsessive desire as Romans and Renaissance princes

The estimated auction price of a stamp that is coming up for sale at Sotheby's puts art in its place. The 1856 British Guiana one-cent magenta, whose last owner was John du Pont, the wealthiest convicted murderer in American history, is expected to fetch $10-$20m (£6-£12m) when it is auctioned in New York on 17 June. For comparison, a Francis Bacon portrait of Lucian Freud set a world record for art last year when it sold for $142m not exactly chicken feed, and more than 10 times the magenta's top estimate. But the Bacon painting is an imposing large-scale triptych. The stamp is literally the size of a postage stamp, since that's what it is, which could make it the most valuable object by weight and size ever sold.