Hundreds of people visit Norwich Magistrates court every day, but how many of them know about the secret building which lies beneath the courthouse floors?

Eastern Daily Press: The undercroft at the Magistrates Court, Norwich. Picture: Jamie HoneywoodThe undercroft at the Magistrates Court, Norwich. Picture: Jamie Honeywood (Image: Jamie HoneywoodArchantNorwichNorfolk)

Hidden below the courthouse, and only accessible via a spiral staircase, itself concealed by a trap door, are the are the ruins of a Norman house which date back to the 11th century.

The flint ruins are one of the oldest existing examples of their type in the country and are comparable to the Music House on King's Street which was built around 1175.

But, unlike the Music House, for hundreds of years the Norman ruins on St-Martin-At-Palace Plain lay forgotten and where completely undocumented.

That is until they were rediscovered by chance in 1981, when archaeologists carrying out a dig in search of Anglo Saxon artefacts discovered evidence of a flint wall.

Eastern Daily Press: The undercroft at the Magistrates Court, Norwich. Picture: Jamie HoneywoodThe undercroft at the Magistrates Court, Norwich. Picture: Jamie Honeywood (Image: Jamie HoneywoodArchantNorwichNorfolk)

Brian Ayers, an honorary lecturer in archaeology at the University of East Anglia, who was part of the 1981 dig, said when he and his colleagues uncovered the wall, they knew they were onto something special.

"The inkling came when we found the first wall and going down and down and seeing it was entirely constructed of stone and then we found the foundations.

"It's an extremely important site.

"There wasn't any documentation about this so when we found it, it was a complete surprise," he said

Eastern Daily Press: The undercroft at the Magistrates Court, Norwich. Picture: Jamie HoneywoodThe undercroft at the Magistrates Court, Norwich. Picture: Jamie Honeywood (Image: Jamie HoneywoodArchantNorwichNorfolk)

Mr Ayers said the ruins where of national significance: "It's one of a dozen of its type in the country and you can compare this to France where there are about 1500.

"To find a building which is still here in the centre of Norwich which nobody knew existed, it's quite extraordinary."

Today, the ruins are only accessible on certain days of the year and during the annual Heritage Open Days festival, but Mr Ayers said he would like to see them opened up to me public more often, he said: "I wish it was open just more than the Heritage Open Days, it's a nationally important building.

"I think it's part of the city's heritage and I think it's important people know it's here."

Eastern Daily Press: The undercroft at the Magistrates Court, Norwich. Picture: Jamie HoneywoodThe undercroft at the Magistrates Court, Norwich. Picture: Jamie Honeywood (Image: Jamie HoneywoodArchantNorwichNorfolk)

The history of the Norman House

The Norman House, the ruins of which were discovered in 1981 prior to the construction of Norwich Magistrates court are believed to be more 800-years-old.

The flint building is thought to have been constructed in 1170 and was built on land belonging to the Norwich Cathedral Priory.

Eastern Daily Press: The undercroft at the Magistrates Court, Norwich. Picture: Jamie HoneywoodThe undercroft at the Magistrates Court, Norwich. Picture: Jamie Honeywood (Image: Jamie HoneywoodArchantNorwichNorfolk)

Evidence suggests the building was looked after by the Cellarer of the cathedral and home to a high-ranking church official who lived on the top two floors of the house.

It is thought the building fell derelict in 1300 and was re-built in 1450.

In the 1600s the building doors were blocked and a spiral staircase cut into the corner above the former latrine.

By the 19th Century the ruins had been covered by a Georgian house which was later replaced by a joinery workshop in the 1940s.

Eastern Daily Press: The undercroft at the Magistrates Court, Norwich. Picture: Jamie HoneywoodThe undercroft at the Magistrates Court, Norwich. Picture: Jamie Honeywood (Image: Jamie HoneywoodArchantNorwichNorfolk)

Today, only the 44ft by 22ft basement walls of the original house survive.

Eastern Daily Press: The undercroft at the Magistrates Court, Norwich. Picture: Jamie HoneywoodThe undercroft at the Magistrates Court, Norwich. Picture: Jamie Honeywood (Image: Jamie HoneywoodArchantNorwichNorfolk)