It's 2 o'clock, and the Friends gather at the Visitor Centre for a preliminary talk.
One entrance to the tunnels as seen from 'Cave Yard'. The original town of Chatham occupied the lower portion of Cave Yard and was demolished to make way for the fort.
On entering the caverns Liz, our guide, explains the use of these rooms during WWII.
The rooms have been restored with authentic equipment to show them as they would have looked during the war when the tunnels -- converted into a civil defence control centre and anti-invasion HQ -- operated under great secrecy.