The cause of the fire was never found

The massive fire, which happened in December 2002, destroyed buildings in the historic part of the city.

Buildings on the Cowgate site had to be demolished after the blaze, because they had been so badly damaged.

Experts carrying out the dig hope to find evidence of life before the 15th Century when the area was one of the most prosperous in the city.

The blaze was described as the most devastating in the capital.

It is still not know what caused the fire, but it was not thought to have been suspicious.

It resulted in millions of pounds worth of damage to more than a dozen properties in linked premises up to seven storeys high.