Radar set to unearth Mile secrets

Experts are taking advantage of roadworks on the historic thoroughfare which involve digging up large parts of the street.

They are hoping that with the use of specialist radar equipment that the holes created as part of a 1.5 million reconstruction project on the road between George IV Bridge and North Bridge will help them peer further into Edinburgh's past.

Initially, the archaeological work will involve radar surveys in the hope of locating any historical buildings such as Edinburgh's Tollbooth and Tyne Gaol.

Both the Edinburgh Tollbooth and Tyne Gaol were used as prisons. The Heart of Midlothian was the name given to the Old Tollbooth by Walter Scott in his novel of the same name. Built around 1403-30, it was originally a booth where tolls were paid and also served as a town hall, prison and an assembly point for Parliament and the Court of Session. When Calton Jail opened in 1817, the Tollbooth was demolished.

It is known that the foundations of these buildings are on the Royal Mile, close to St Giles, although it has never been possible to pinpoint their exact locations.

But by using non-destructive radar technology suitable for identifying layer depths, utilities and archaeological features, city archaeologist John Lawson and his team are hopeful of success.

After the areas have been identified, the city council plans on erecting brass plaques to highlight the significance of the sites.

Mr Lawson said

: "It's known that the foundations of Edinburgh's tollbooth are on the Royal Mile, near St Giles Cathedral. Plans from the late 17th and early 18th century plot their location, but we're excited to be able to pinpoint them exactly.

"Built in late medieval times, the buildings were demolished in the early 19th century. In their heyday, they played an extremely important role in the city, as a town hall, Edinburgh's tollbooth and the town jail.

"This work will allow us to accurately interpret what remains for both residents and visitors to the Royal Mile."

The modern road reconstruction, which involves re-laying thousands of existing traditional granite setts, more commonly known as cobbles, will give experts the chance to identify where these buildings lie.

The setts will be used to maintain the historic appearance of this section of the Royal Mile.

Historic Scotland, Edinburgh World Heritage Trust and Conservation Planning have all approved the design. The reconstruction project is being undertaken to prevent further damage to the road and to avoid any future need for unplanned emergency repairs. The work will be completed by early 2007.

Excavations will be made as the project rolls on, although any foundations discovered will be left intact and undisturbed.

Councillor Andrew Burns, the city's transport lead, spoke of his excitement at the project.

He said: "These crucial works, to restore the cobbles of the Royal Mile to their rightful glory, are providing a fantastic opportunity to learn more about the history of our city."