Police detectives have launched a new appeal for information 40 years on from the mysterious death of a 15 year-old boy central London.

The death of the welsh teenager, who was found in the middle of Euston underpass in the early hours of the 19th of January 1976, still goes unexplained.

The body of Peter Watts, the 15 year-old from Colwyn Bay, North Wales, was discovered around half a mile from Euston station at 1:30 in the morning. A passing cab driver called an ambulance but Peter died in hospital an hour later.

Four decades on, the Met's Special Casework Investigation Team, are releasing details of Peter's death in an effort to trace anyone who is yet to speak to police about the incident.

Detective Inspector Susan Stansfield, who is leading the investigation, said: "Despite numerous appeals, mystery still surrounds the death of Peter Watts. He came from a loving and close-knit family but tragically his parents both died without the answers they were seeking.

“We've never had any information to suggest that anyone else was involved in Peter's death but, for the sake of his brother, we would like to speak to anyone who may be able to assist."

Following extensive police appeals in both England and Wales, officers were able to piece together some of Peter's last known movements.

Peter left a note to his parents at his home on the day he was found dead saying he was planning to help a school friend with homework and would return soon.

Peter’s brother Mark Watts, 57, told ITV News: “I was the last person to speak to him. I put my head around the bedroom door and said goodbye before I left the house with Mum and Dad and he seemed perfectly normal at the time. No indication that anything was about to go wrong.”

Investigations found that Peter left his home to purchase a train ticket from Colwyn Bay station to Chester. He is thought to have travelled on the 17:15hrs, Holyhead to London train, but failed to leave the train at Chester. It is then thought he continued on to Euston, possibly arriving at 21:15hrs.

Apart from the guard who sold Peter his train ticket at Colwyn Bay, there were no further confirmed sightings of the 15-year-old.

A post mortem examination gave the cause of death as head injuries consistent with a fall. There were no marks on Peter's body to indicate he was pushed from the bridge or had been involved in an earlier struggle. There was also no evidence of any sexual assault. Officers established that Peter was missing his watch and glasses when he was found. These items have never been found.

Anyone with any information is asked to contact the Incident Room on 020 7230 7963 or Crimestoopers anonymously on 0800 555 111.