The wiring loom on your car carries smoke from one device to another, pumped around the system by the alternator, and when a wire springs a leak it lets all the smoke out and everything stops. Starter motors require lots of smoke to work properly, so they have very thick wires going to them. The battery stores up lots of smoke dissolved in battery acid, which is why they were once called accumulators, until it became apparent that we unwashed home mechanics would twig to the secret. Naturally, if you try to dissolve too much smoke in your battery it will escape through those little holes in the top, which is why those batteries with sealed tops explode when they get too much smoke in them.
With regard to Joseph Lucas and his wrongfully sullied reputation, why is he so maligned? Why are Lucas components more likely to leak smoke than, say, Bosch? Because Lucas is British, and all British made things leak. British motorcycles leak oil, British sports cars leak rain, British brakes leak fluid, and British governments leak military secrets. So naturally British electrical components leak smoke.
