I hadn't come across this before. @ukwarcabinet recently linked to some informal notes of a War Cabinet meeting held on 8 February 1940. It was pretty quiet, even for the Bore War, and 'Some of the subjects discussed were rather discussed by way of filling in time'. Including this:
At the end of the Meeting there was a reference to a scare which had started through a red balloon floating about in the Eastern Counties. This balloon had been sent up for meteorological purposes, but it had apparently given rise to a scare that gas balloons were being let loose by the Germans. The London Passenger Transport Board had told their employees to be ready to put on their gas-masks!
It seems they weren't particularly concerned by this incident, despite what it might have said about the fragility of morale. The scare wasn't kept secret; the Manchester Guardian had already reported it that morning (p. 7), with some extra details:
"ENEMY GAS"
Harmless Balloons Start RumoursExtraordinary rumours in Eastern English and Scottish coastal districts followed the discovery yesterday of a number of small balloons. These were harmless British meteorological balloons but stories which had spread in various parts of the country had suggested that they were of enemy origin and that they contained dangerous gas.
At King's Lynn (Norfolk) these stories led to the police issuing the following statement:--
The enemy has dropped balloon toys which may contain gas, highly inflammable, and explode on being touched or handled by lines attached. Police and observer corps should be informed if any are found.
The balloons are used for testing atmospheric conditions and occasionally they sink to the ground without bursting. They are harmless except that they contain hydrogen, and are therefore likely to explode if brought into contact with a naked flame.
So the story is that British meteorologists launched some weather balloons which came down in the eastern parts of England and Scotland. Passers-by found them, thought them suspicious, and reported them to authorities, which in turn made public statements that they were dangerous German weapons -- either incendiary devices or actual poison gas bombs. In more normal times, it's unlikely that a stray weather balloon would be interpreted as something dangerous, just something curious. Now, with the war strangely calm and the expected bombers nowhere to be seen, it's more understandable that people would be jittery and overreact to mundane (if rare) sights (it had happened before and would happen again). And it certainly had to be considered that the Germans might try to use some sort of secret weapon against Britain. But the fact that the scare seems to have happened simultaneously in widely separated places -- London, Norfolk, Scotland -- suggests that there was something else going on too. Was the Met Office trying out a new balloon design? Perhaps it was the red colour mentioned in the War Cabinet discussion which made the balloons look especially sinister? Anyway, it's another scare to add to my list.
PS I think I should get credit for not mentioning Nena. Until now.