''A mythical Beatles gem''

Listen Listen to music journalist Jonathan Wingate (5 mins 22 secs)

The track was performed just once in public

Hard-core Beatles fans around the world are anxiously hoping for the release of Carnival of Light, a 14-minute long experimental track.

The song was recorded in 1967 just after the vocals for Penny Lane were taped.

Music pundits say it is Paul McCartney's most obvious tribute to the classical composer Karlheinz Stockhausen - and Paul McCartney himself has been trying to get the track released for years.

Music journalist Jonathan Wingate explains what all the fuss is about.

First broadcast 16 November 2008