A musical mystery today surrounded Britain's highest mountain after a piano was discovered near its summit.

Volunteers clearing stones from the 4,418ft peak were astonished when they discovered the musical instrument on Ben Nevis. An appeal has now been launched to find out how and why the piano came to be within 200 metres of the top of the mountain.

The piano was recovered at the weekend by 15 volunteers from the John Muir Trust, the conservation charity which owns part of Ben Nevis.

The squad was removing litter and stones called cairns from the summit plateau when they spotted the top of the piano.

"Our guys couldn't believe their eyes," said trust director Nigel Hawkins.

"At first they thought it was just the wooden casing but then they saw the whole cast iron frame complete with strings.

"The only thing that that was missing was the keyboard - and that's another mystery.

"Maybe it's hidden somewhere else on the mountain."

He added that a biscuit wrapper with a best before date of December 1986 was found under the piano, giving a clue as to when it was taken there, but not why.

Volunteer group organiser Sandy Maxwell, of Glasgow, said this was the largest, heaviest and most unusual object they had found on the mountain.

"We have a constant battle against litter being left on Britain's highest mountain - but this elevates being a litter lout sky high into a completely different category. We are now trying to track down who took it there.

"We may even give them an outstanding invoice for 20 years storage of a piano under a cairn on Ben Nevis."

After finding the piano, the volunteers broke it up and asked around 30 members of the public to help carry bits off the mountain. Mr Maxwell said they believed the piano was taken to the top of Ben Nevis for a wacky stunt.

"We assume it would be a student stunt or charity run but we certainly have no record of it," he added.

"We would be very keen to hear from anyone with information about the piano."

How the mystery of the Ben Nevis piano was solved