170 Swiss soldiers walked into Liechtenstein at night

A hundred and seventy infantry soldiers of the Swiss army set out on night manoeuvres on 1 March 2007, in the canton of St Gallen, in rain and with no moon. They strayed a kilometre and a half off the planned route and ended up inside Liechtenstein, the 160-square-kilometre principality that sits against Switzerland's eastern edge.

At some point somebody looked at the map, they turned around and went back. Nobody saw them. Nobody stopped them. There was nobody to do it: Liechtenstein disbanded its army in 1868 because it cost too much to keep, and has not had a single soldier since.

What turns the episode into perfect comedy is how the invaded party found out. Nobody in the principality knew a thing until the Swiss army itself telephoned to apologise. A Liechtenstein spokesman settled the matter with exactly the line it deserved: there was no cause for concern, it was not as if they had come in with attack helicopters.

So Switzerland, which has gone two centuries without entering a war and has underground shelters for its entire population, has invaded a neighbour exactly once in modern history: at night, by mistake, and having to break the news itself.