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Secrets from inside a WWI trench

3 November 2011 Last updated at 07:15 GMT

A team of archaeologists has started one of the largest investigations ever mounted on the WWI battlefields.

They have been given permission to excavate a large section of trenches and tunnels close to the huge Lochnagar Crater.

The archaeologists will also be uncovering trenches, and recovering the bodies of those who died during the fighting in the Battle of the Somme.

The BBC were given a tour inside a British tunnel that was dug in March 1916 by Peter Barton and Simon Jones from La Boiselle project team.