A lock of Beethoven’s hair is going up for auction after being snipped off by the composer himself almost 200 years ago.

Beethoven gave the dark brown and grey strands to his friend, pianist Anton Halm, in 1826, just a year before he died.

The precious and “substantial” lock is expected to fetch £15,000 when it goes under the hammer at Sotheby’s, London, next month.

Beethoven only gave it to his friend after he was originally tricked with hairs from a goat.

Simon Maguire, director and senior specialist of books and manuscripts at the auction house, said the lock had “arguably the best story behind it of any to appear at auction”.

Halm was arranging Beethoven’s Grosse Fuge op.133 for two pianos, composed when he was deaf and now seen as one of his greatest achievements, when the pair became friends.

“Halm asked for a lock of Beethoven’s hair for his wife Maria….” Mr Maguire said.

“The hairs arrived a few days later, supposedly Beethoven’s, but had in fact been cut from a goat.

“When he had finished his arrangement, Halm brought it and the hair to Beethoven.

“The composer was furious that his friend had been deceived, and promptly snipped off some hair and gave it to him, declaring it to be genuine.”

The trick sparked “conflicting accounts of who was to blame for the original prank, one indeed implicating Beethoven himself”, he said.

Beethoven’s biographer, AW Thayer, later spoke to Halm about the story, who told him that the composer had “turned to me with a fearsome expression and said, ‘You have been deceived about this lock of hair!’.

“‘See what terrible creatures I am surrounded by, whom respectable people should be ashamed to be with. You’ve been given the hairs of a goat’.

“And with that, he gave me a sheet of paper containing a considerable quantity of his hair, which he had cut off himself, telling me ‘This is my hair!’.”

Halm, who died in 1872, played for Beethoven frequently.

The pianist and composer gave the hair to his pupil Julius Epstein, who died in 1926, and it has been kept in his family ever since.

Sotheby’s will offer the lock of Beethoven’s hair as part of the Important Manuscripts, Continental Books and Music sale on June 11.