Police are to issue a fresh appeal for information about the murder of a 12-year-old boy who was stabbed to death in East Sussex 40 years ago.

Talented musician Keith Lyon went on a trip to the shops when he was stabbed to death on the South Downs. The murder weapon was a serrated kitchen knife.

His body was found next to a path running between Ovingdean and Woodingdean, near Brighton, at 4.15pm on Saturday May 6, 1967.

Witnesses later spoke of seeing a group of boys scuffling at the spot where Keith was discovered. A knife was found near a local school and there was evidence that someone had tried to wash their hands and clothes at a toilet block.

Keith's younger brother Peter Lyon is expected to appear at a press conference organised by Sussex Police.

Detective Inspector Tim Nunn will give a briefing about the recent work that has been carried out on the case and issue a further appeal for information.

The murder investigation was one of the biggest ever seen in Sussex. More than 5,000 youths had their fingerprints taken and 80,000 home visits were made.

No-one was ever charged with the murder.

The investigation has been subject of a number of reviews over the years. In 2000 and 2001, it featured on the BBC television programme Crimewatch.

Keith is buried at Ovingdean Church alongside his father Ken, a professional musician who died 16 years ago.

The briefing will take place at Sussex House, Crowhurst Road, Hollingbury, Brighton at 10am.