Mystery surrounding one of the county's medieval legends has been reignited after an ancient stone coffin linked to Richard III was unearthed on a building site.

The solid stone sarcophagus was discovered in the grounds of a property in Earl Shilton, by the home's former gardener Reg Colver, where it had formed part of a water garden built in the early 1900s.

Archaeologists believe it dates from the time Richard died and could have been buried in the same church, Greyfriars, which once existed near Leicester Cathedral.

Richard Knox, of the county council's archaeological services, said: "It is an important medieval artefact in its own right, it also shows the strength of the Bosworth myth which makes all local medieval finds somehow relevant to Richard and the Battle of Bosworth."

Legend has it that after Richard's death at the Battle of Bosworth in 1485, he was buried in Greyfriars Church, but some 50 years later his grave was ransacked and his bones thrown into the River Soar.

His coffin is then said to have been given to the landlord of the White Horse Inn, in Gallowtree Gate, Leicester, where it was used as a water trough before being broken up and used to repair the yard and cellar steps in 1758.

Archaeologists have said they are confident the coffin unearthed yesterday is not that of Richard, but would never be able to rule out the possibility.

Mr Knox said: "It is also quite possible that Richard's coffin is still buried at the church at Greyfriars and was never dug up at all.

"However, it is quite possible this is a coffin dug up from the Greyfriars and we know that it was used as an animal trough in Leicester before it was brought to Earl Shilton in 1903.

"This is why the idea of it being Richard's coffin came about."

Mr Colver, 69, from Barwell, first became aware of the coffin when the owners of the bungalow, where he worked as a gardener for 10 years, told him what it was.

His initial calls to the Richard III Society were rebuffed, but when he learned the site was to be developed, he decided to try again and contacted the museums service, which took up the challenge of removing and examining the coffin.

Mr Colver said: "It is part of history and even if it was not Richard's, it was built for somebody very important and at least it can now be used as another talking point in the debate."

An episode of BBC One's The One Show, at 7pm on Monday, will delve further into the mystery.