Royal Mile dig helps unlock secrets of Deacon Brodie jail

Part of the 400-year-old Tolbooth was discovered under the Royal Mile during the 1.5 million facelift of the road.

Although it was known that its entrance was marked by the Heart of Midlothian stones outside St Giles' Cathedral, the exact location remained a mystery until now.

Head archaeologist John Lawson said his team had found a ten-metre wall which formed part of the building's foundations - including an offshoot which could be part of an ancient jail cell.

Mr Lawson said: "Parts of this building date back to as early as 1386 and although it was remodelled a number of times, this wall is likely to be at least 400 years old.

"The Tolbooth was, from all account, notorious for being a very bad jail in the 16th to 17th century and the conditions were pretty bad.

"The wall has been lucky to survive. It is right underneath the road, where traffic has been going up and down for years, it has had drains running past it and gas pipe just over it."

During its chequered past the Tolbooth was used as the Council Chambers, the Scottish Parliament sat there and it was the site of the High Court.

Latterly it became the Old Town jail, before it was knocked down in 1817 to widen the road.

Amongst the notorious criminals imprisoned there before they were hanged was Deacon Brodie - the respected councillor who prowled Edinburgh's streets at night robbing houses.

He was reputedly hanged at the Tolbooth on October 1, 1788, using gallows he had designed and funded the year before.

Mr Lawson added: "The Tolbooth is laden with history and being able to mark exactly where it lay is a significant step in charting Edinburgh's past.

"It's one of Scotland's iconic buildings and the scene of many dramatic events in Edinburgh's colourful history.

"Uncovering it gives us the opportunity to interpret the findings and preserve this important landmark."

He said more investigations were to be carried out on one section of the wall which has an extra part on it which could form part of a jail cell.

"We're not sure yet exactly what it is, but it could be a cell or part of a cellar," he said.

"We will dig a small trench through the demolition rubble to find out what is in the middle of the building at that point. It's really very exciting to actually find parts of such an important building in Edinburgh's history."

Edinburgh's streetscape leader, Councillor Bob Cairns, said: "It's tremendous that the works to restore the Royal Mile setts have provided us with an opportunity to learn more about our city's past and preserve it for future generations."

He added: "The archaeologists are hopeful to find more as they go down the Mile.

"We have no record of exactly where the building was - I think attitudes were very different in those days - people weren't as sentimental about old buildings. However, it would cause quite a traffic problem on the Royal Mile if it was there now."

The site will now be preserved by terra sheeting and then recovered. When the road is eventually relaid, there will be copper setts to mark its location.

Work on the reconstruction of the road surface between George IV and North Bridge began in January this year.

The archaeological work involved radar surveys in the hope of locating any historical buildings such as the Tolbooth and Tyne Gaol.

The next stage of work - from St Giles' Cathedral down towards the Canongate - is expected to uncover more of the building.

It is also hoped to uncover some remnants of the luckenbooths, the city's first permanent shops that housed jewellery workers, and other trades, more than 500 years ago. The work will be completed by early next year.