The sum was the second highest ever seen for a work in this category, only behind Peter Paul Rubens' The Massacre of the Innocents, which famously took £45m in the same room in July 2002.
The 3ft 1in x 4ft 2in (93cm x 1.26m) oil on canvas painted in 1835 came to auction from the collection of the 85-year-old Earl of Rosebery, whose son Lord Dalmeny is chairman of Sotheby's UK.
With a prestigious and unbroken provenance as well as its exceptional state of preservation (it had been kept behind glass until it was removed for the auction viewing), the £15m-20m estimate was surpassed as two phone bidders took the price up in increments of £500,000.
A third phone bidder entered the fray at £21m, but the lot was eventually knocked down to a buyer bidding through Melanie Clore, the global co-chairman of Sotheby's Impressionist & Modern Art department.
Overall the sale performed well, with 36 of the 43 lots getting away (84%). The £47.1m hammer total came in above the £32.2m- 44.9m estimate.
The Old Master sale the previous evening at Christie's was a slimmer affair, with 36 lots of which 27 got away for a hammer total of £11.7m. The top lot was a Sir Anthony van Dyck (1599-1641) portrait which fetched £2.5m (estimate £2.5m-3.5m).
A full report of the series will appear in a future issue of ATG's print publication.