A 13th century copy of the Book of Psalms realised a fortune for a British collector last week. The 700year-old illustrated prayer book, which has never been seen in public, was sold in London for a record £2.7 million sterling.

The Burdett Psalter was bought by an anonymous private collector who paid almost double the estimated value. The price is a record for a French illuminated manuscript and the third-highest price paid for an illuminated manuscript.

The 13th century copy of the Book of Psalms had been in the family of Ms Jane Burdett from 1634, but was sold privately to the collector in 1990. For nearly two decades before that, the descendants of British Midlands baronet, Sir Francis Burdett, kept it locked in a cupboard after discovering its value. The book is thought to have been commissioned by a French knight in the Holy Land in the 1280s.

After the defeat at Acre of the Christians by the Muslims, the knight Jean de Villiers smuggled it out with him to Cyprus where he died. The book, with its gold illustrations, was brought to England where it passed through three families unknown to scholars and art historians until 1990.

Sotheby's specialist Dr Christopher de Hamel said: "This is the first time that this book has appeared on the open market and today's price is a triumph for the Crusaders."