Yachtsmen entering the River Crouch in Essex will pass between Foulness Island to port and Dengie marshes to starboard at a place called Shore Ends.

About half a mile into the river they will notice an unusual World War II gun emplacement to starboard which has a sinister looking hooded look-out atop a pill box.

But when you walk along the sea wall to this fortification (see yesterday’s blog) you discover that the look-out is a reinforced, three storey, concrete, roundhouse standing separate from the pill box in the field 30 yards behind the sea wall and the other side of a dyke as the picture shows.