John Walsh: In 1937, the enemy invasion was youths on bikes in leather shorts

Tales of the City

What a charming picture of pre-war Britain is conjured up by the newest selection of National Archive documents released by MI5. In the summer of 1937, down lanes of Queen Anne lace, through sleepy villages and seaside towns, came the enemy invasion: a score of flaxen-haired, well-scrubbed German youths in brown shirts and black leather shorts, riding their bicycles all over the country, by way of Liverpool Street station.

Despite the leather shorts, which today would suggest a travelling band of Bavarian rent boys, they exuded innocence and health. One can imagine them singing hearty songs about knapsacks, and charming dim English frauleins. It obviously worked: they were welcomed with open arms by the Spalding Rotary Club, which entertained them with a sausage-and-mashed-potato supper by the fire. Yes, they were members of the Hitler Youth – but that was no reason to be inhospitable.

MI5 were on their case, though. They didn't trust the cycling Aryans with their sharp blue eyes and strappy lederhosen. According to the newly-released files, they monitored their movements, worried about their being "in possession of cameras" and having "various pictorial Scout movement badges" sewn onto their clothes. What did it mean? Were they the first wave of an actual invasion?

It's not the first time the security services suspected seemingly innocent people of espionage. In the 1790s, Wordsworth and Coleridge were followed on their long walks in the Lake District by the Romantic era's version of MI5, after they were heard uttering the words "The spy knows her" (they'd been discussing Spinoza). But in 1937, MI5 were right to be concerned. The cyclists were in fact gathering information. "Impress on your memory," they'd been told, "roads and paths, villages and towns, outstanding church towers and other landmarks ... Perhaps you may be able to utilise these some time for the benefit of the Fatherland ... Estimate the width of streams. Wade through fords so you will be able to find them in the dark ... "

They were also, it seems, trying to infiltrate the Boy Scout movement and fill it with Nazi propaganda. Would that have worked? Try to imagine the conversation between a boy scout and a Hitlerjugender.

Rolf: Goot afternoon. My name is Schmeisser. What would you say is zer vidth of zis charming stream?

Scout: I've no idea.

Rolf: How many houses in zis village have a telephone?

Scout: Haven't the foggiest.

Rolf: Vot is the tallest church tower around here, from where you might be able to see zer approach of zer enemy – ach, nein, sorry, zer ice-cream-dessert van?

Scout: Search me. Are you German? My name's Jeremy.

Rolf: Ve are a group of friendly young Germans, cycling in your lovely country for zer bracing ozone and humorous cultural exchanges about football, with no interest at all in subjecting you to despotic rule by zer glorious Third Reich.

Jeremy: I don't really know what you're on about, actually.

Rolf: Vot is that badge you have?

Jeremy: This one's my Beaver Scout Animal Friend badge, that I got for looking after my guinea pig, Gladys. This one's my Cub Scout DIY badge for making a Balsa Wood Letter Holder and Towel Rail. This is my Circus Skills badge ...

Rolf: You cannot spend all zer valuable time of youth at childish hobbies. What else do you do?

Jeremy (thinks): We eat lots of baked beans. I've learned to thread a neckerchief through a woggle. And we sing songs about doing our best. That's pretty much it really.

Rolf: Don't you want to go cycling in bracing fresh air, performing manly exercises out of doors with laughing fellow athletes, and work for the betterment of the Aryan race?

Jeremy: Not really. Cycling gives me nosebleeds.

Rolf: Would you not like to visit Germany and admire its mighty forests and seas, which will fill you wiz a sense of cosmic destiny?

Jeremy: We're going to Cookham Dean this summer, actually.

Rolf: Have you not heard of the threat from the Jewish race, who own all the world's banks and drink the blood of Gentile babies?

Jeremy: No. But I'll ask the junior scoutmaster about it. He knows everything, does Mr Cohen.

Rolf: Would you like a go in my black leather shorts?

Jeremy: No thanks. Leather brings me out in hives.