In readying the southern British coast for invasion, besides the usual pillboxes and barbed wire, there was also the Flame Fougasse. A camouflaged oil drum filled with petroleum, lime and tar that could be ignited and then rolled into the path of an invader. But further offshore were pipes, laid beneath the surf, through which oil could be pumped to spread over the surface of the water. Then, as the enemy came closer, the oil could be ignited with a flare pistol. Viola- an instant wall of flame to incinerate would be invading troops.