The LP was dedicated to Jimi Hendrix by the artists

The signed and dedicated McGough and McGear LP was found in a collection of other old records as staff sifted through donation boxes.

Inquiries by the management of the Oxfam store in Henley have been unable to find the mystery donor, but verified it once belonged to Hendrix.

It is being auctioned in a collection of pop memorabilia at Christies.

Michael McCartney wrote to us saying that he hopes the sale makes a million for the charity Jill Partrick

Jill Partrick, the shop's record specialist, said they have no idea how it came to be in Henley.

"It just came in midweek, and it was with just another batch of records that were brought in - we've never been able to find out where it came from," she said.

"Lots of theories have been put up that maybe Jimi Hendrix had a local girlfriend that he gave it to."

Personalised copy

McGough and McGear was a project by Mike McGear, Paul McCartney's brother, and poet Roger McGough.

It was produced by Paul McCartney and featured a host of 60s stars including Hendrix and members of the Yardbirds and Walker Brothers.

The album handed into the Oxfam store is the personalised signed copy given to Jimi Hendrix by Mike McGear and Roger McGough.

Mrs Partrick and her husband David spent more than 18 months trying to track down the musicians to verify that the record had been given to Hendrix.

"Michael McCartney wrote to us saying that he hopes the sale makes a million for the charity," said Mrs Partrick.

"Christie's have estimated the record at �2,500 - �3,000 but I think they're being conservative.

"Hopefully we'll make more than that, but even if it doesn't I'm pretty sure this is the most any Oxfam record will have been sold for."