Nothing whatsoever happens.
Turns out the battery is dead as a door nail. Some freak radio contact seems to have drained it over night, and it was tired and frail to begin with. This is bad news, because I am supposed to be on a yacht by 12 noon sharp, and I have about two hours worth of driving to do to get to the marina. The ferry which might take me to a place where I could catch a train has just left. Luckily, Tony who lives downstairs is around.