Stretching 440 miles from the Swiss border to the North Sea, the line of trenches, dug-outs and barbed-wire fences moved very little between 1914-1918, despite attempts on both sides to break through.

Lt Col Rebekka Straessle, the head of the Swiss border guard, also gave evidence to the committee about the use of camera technology at the Swiss border. She said there are cameras at most ...