In 1940 a network of defences was hastily built all over the British Isles to prevent an anticipated German invasion. Sited at road junctions, canals and other strategic points these constructions were called "pillboxes".Despite the passage of time many of these remain as permanent monuments and a silent tribute to the courage and tenacity of the British people in the dark days of 1940.This photo book records some of what remains today.Contents1. Introduction.2. The Images. · Southern England · London · East Anglia · Central England · North West England · Northern England3. Pillbox Types.4. Operation Sealion - The German Plans for Invasion.5. The Home Guard6. Useful Reference Sources