An urban myth?

In 1805 the Royal Navy inflicted a devastating defeat on the French fleet off the western coast of Spain. Realizing that the English were near unbeatable at sea the French attempted to defeat the Navy on land. To this end French saboteurs released flocks of particularly nasty carnivorous bats into Chatham and Woolwich dockyards eastwards of London. The idea being that this pteropine terror would startle dockyard workers causing them to fall into the dock and drown, so demoralizing others and slowing down activity. The bats were sourced from caves in central France later totally destroyed in a little recorded earth tremor together with the bats(seismology was still in its infancy), - so giving rise to the warning "Bat" when they were seen flying at dusk(the exact naval phrase was never written down, probably impolite). The attempt failed because the dock cats were as tenacious as their human counterparts and would not give up their staple diet of mice to the bats (rats were too large for the bats). So the bats moved out, surviving in the countryside in barns and such, almost becoming extinct. Salvation came for them with in the mid 19th century with the building of - railway tunnels. These artificial caves were ideal for the bats, save for the occasional lungful of smoke. As railway building progressed the bats moved closer to London. Initially, they were no problem on the Undergound(1863), as although the running track was in tunnel, the stations were open to the air, eg Bayswater, so bats flying into the stations ahead of the trains could escape upwards. Problems started with the construction of the "tube" railways from 1890. Tunnels were cleaner because of electric haulage, the mice population exploded, but single track, the trains were a close fit within the tunnel, and stations were also totally enclosed, albeit in a larger diameter tunnel. Fortunately for the bats, the tunnel walls were made of recessed iron panels so the bats could safely roost at the side of the tube outside the loading gauge. This enabled the bats to grow to some considerable size before being struck by a train. Two aspects of survival came into play - 1 bats roosting in the approach to the station tunnel had somewhere to escape to, whereas those as the exit could not outfly the train and were probably killed. - 2 where a tunnel was curved it also had to be laterally widened to accommodate the overhang of the train. This widening was was usually more than necessary and so gave the bats a little more space in which to live, so migration to these tunnel positions occurred, and also where mice are abundant eg Bank station. Coincidentally, curved approached tunnels are usually followed by curved station tunnels and therefore curved platforms.Though rarely seen, the bats have proved impossible to exterminate, possibly due to virtually unlimited supplies of mice(reportedly 500,000 in central London), in turn living on food dropped by passengers.Maybe in an attempt to slow down colonization of the Underground no EMU passenger stock has ever been built with horizontal handrails which would allow bats to hitch a ride, especially to a depot. (Imagine the chaos!). The exact origin of the bats was unknown until a french naturalist in London in the late 1890's - the war with France had finished by then(GB 1 - FR 0) - suggested they seemed to have many similarities with a recently extincted species of bat from the Central Massif of France. On examination of the evidence available it was decided that they were the same species which had lived in caves there. These caves were identified as "Les Grottes du Gappe". Now the bats had a name - Gappes, even if it was french. As the bats could be disturbed by the noise of an incoming train at these stations, flying into the station tunnel and startling passengers, maybe causing them to fall onto the track, many people have, due to no apparent reason other than bats - hence the presence of the "suicide pit", the audible warning "Mind the Gap(pes)" is sounded and repeated as the train nears the platform until just prior to departure. Prior to the audible warning the exhortation was written on the platforms in the anglicized form "Mind the Gap" to be similar to "Mind the Step". Since these precautions were taken the bats have adapted again and have found they can fly alongside the train if they keep out of gauge (train-surfing?). This has given rise to another message -"Mind the Gap(pes) between the train and the platform".On hearing either of these warnings passengers should look carefully around them, and if they have long hair tuck it away as a precaution, and step cautiously to or from the platform or train.Of course, "Mind the DO(O)RS" has a completely different origin.