I watched a fascinating documentary a couple of days ago about the so called 'black propaganda' units operating in the Second World War. These used dirty tactics to try to demoralise the German troops, including dropping pornographic leaflets and spreading rumours about soap being rendered from all the amputated limbs in Austrian hospitals. Some of the stories were very funny, while others were rather horrifying. One of the funniest moments was an interview with a woman (now in her late 60s) who — as an innocent young girl of 22 — was asked to doctor a photograph of Hitler to show him holding his penis, underneath which would be the legend 'What we have we hold' in German. As she put it, she would "laugh like a drain" about it now, but at the time it was deeply shocking. Hilariously, the instructions she received were to make the penis realistic, "but not too large". You probably won't be surprised to learn that quite a number of the pornographic propaganda leaflets have survived to this day; soldiers tended to throw away the usual kind, but hung on to the porn.

An ex-Daily Express journalist called Sefton Delmer directed a lot of the propaganda effort, some of which was very elaborate. They set up a fake German Radio station called Deutcher Kurtzwellensender Atlantic, which featured a seductive young woman called 'Vicky' (who was a Jewish woman called Agnes Bernelle). She flirted with the sailors on the U-boats while surprising them with accurate news of their relatives back home. One of the key principles of propaganda is that you have to give people the truth so that you can slip through a few lies. I think that 'Vicky' might have raised morale on the U-boats rather than the reverse; one U-boat sailor who was interviewed was certainly very excited when he was offered a look at a photo of Vicky — "Can I make a copy?"

Some of the tactics were really low. Somehow, the propaganda unit got hold of so-called 'dead letters' sent by grieving mothers to their dead sons because they couldn't accept that they had died. The unit sent letters back to the mothers, telling them that their sons were alive and well and hiding in a neutral country, and would send for them after the war. That's tantamount to torture, and I can't imagine that you could hurt someone more without physically harming them. As Delmer said, there's no Geneva Convention for propaganda.

Both sides exploited the most fundamental instincts of humans. The Germans dropped magazines done in the style of 'Life' magazine. Read from the front, the images were seductive girlie images, but from the back ('Death') there were photographs of skulls in British army helmets. The messages accompanying it put across the idea that if the Allies were about to win, it would be really pointless to die in the last few days of the war — you would miss celebrating the victory with your sweetheart.