JS Bach's handwritten manuscript for his Prelude, Fugue and Allegro for lute or keyboard in E flat major has sold for £2.5m ($3.3m).

That's a new auction record for a manuscript by Bach at auction.

This is one of three Bach instrumentals left in private hands

It headlined Christie's sale of Valuable Books and Manuscripts in London on July 13.

The piece dates to circa 1735-1740 and is often described as one of Bach's most important solo instrumental works from this period.

Complete scores of Bach's compositions are extremely rare, with a grand total of 10 known to be in circulation on the private market.

Only three of those are instrumental, making them particularly desirable.

While there are few complete scores available for collectors to buy, Bach did leave a significant collection of his works on paper.

Most are in the permanent collections of various institutions, with the Staatsbibliothek in Berlin holding the vast majority.

Christie's states: "Fewer than twenty Bach manuscripts of any kind, including fragments and partially autograph or amended orchestral parts, have been offered for public sale since 1970: all were scores or parts for church cantatas.

"According to our research, no manuscript of any kind for a secular or instrumental work has appeared at auction since the present manuscript in 1968

The sale also featured a collection of items belonging to the great physicist Albert Einstein.

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