The 18th-Century score for the final scene of Act IV went under the hammer to an anonymous buyer at Sotheby's in London.

The manuscript is virtually complete and written entirely in the composer's handwriting.

It is also considered particularly valuable as a mark of Mozart's singular genius because he is believed to have written the entire 10-page act in one sitting.

The Marriage of Figaro, composed in 1786, has become the most-performed of all Mozart's operas and is widely considered to be his dramatic masterpiece.

Controversy

The score in the auction was written for the woodwind, brass and timpani and comes as Mozart's comedy of manners and morals reaches a close.

The opera tells the story of a philandering count who is increasingly outwitted by his servants - and eventually his wife.

In the final scene the count has seen the errors of his lustful ways. The countess forgives him, as do his somewhat triumphant staff.

Despite the popularity of the Marriage of Figaro, the piece caused controversy in Mozart's day.