Step inside the great auction houses of the world and discover the bidding frenzies within. In this opening episode, Sotheby's sells The Lock by John Constable.

The work of designers such as Finn Juhl, Shiro Kuramata and Arne Jacobsen comes to the salerooms of London in a week dedicated to design classics.

The blouse Judy Garland wore in the film The Wizard of Oz goes up for sale in London, as do Warwick Castle's ornate Grimani Tables - valued at half a million pounds each.