As we see here, Tilbury Fort has been protecting London for over 500 years. It is situated alongside the River Thames with views out to the estuary and is only a museum now.
We go inside and explore England's finest example of a 17th century bastioned artillery fort that remained active into the 20th century.
Officers houses built in 1600 - front
Alan playing his part for the photo
The amnunition had to be stored underground in case of explosion