British export licences are required for watercolours worth more than pounds 39,600; Sotheby's exported the scroll without a licence, not thinking it was worth that much.
The painting is the work of Giuseppe Castiglione (1688- 1768), a Jesuit priest who worked for three Chinese emperors. A footnote in Sotheby's catalogue, where the estimate was pounds 20,000- pounds 34,000, alerted the National Museums of Scotland to its origin, and they demanded it back.
It was finally agreed that the work would be returned to Britain after the sale and an export licence applied for; British institutions would then be given three months to match the sale price.
The fierce bidding battle was won by Giuseppe Eskenazi, a London dealer.