HARGATE FOREST TUNNELS - May 2019
Between 1940 and 1941 a network of tunnels were excavated sixty feet below Hargate Forest on the south side of Broadwater Down. Whilst there is no documentary evidence as to why these exist, there are strong rumours that the tunnels would have been used as an underground operations room for Lt. General Montgomery in the event of a german invasion but this isn't necessarily true.
Today the three entrances to the flooded tunnel system still remain in the forest and actually sit next to footpaths used by the general public. They all have metal gates and locks to prevent access although there is plenty of evidence that they have been accessed many times over the years.
There's a very interesting reference to the location on the Subterranea Brittanica website here: