Forget any ideas that media management is a recent art. Any study of the art of propaganda might not immediately draw you to a documentary about barrage balloons, but for the teacher looking for a different slant this 25-minute video has much to offer.

Actually, it is more reassurance than propaganda. Made in the late 1930s and released in 1940, this film leaves Brits in no doubt about being all in this together. Ordinary blokes - chauffeurs, salesmen, clerks - leave their jobs and learn to handle arrage balloons.

We are reassured that the barrage balloons themselves are a major deterrent to modern bombers using dive bombing techniques (which they were, and we see them being deployed across the land).

The central story of the film is of the protection of the Forth Bridge from bombers during the Second World War. However, it draws in a wealth of fascinating period detail about the way the war was fought and the way Brits saw themselves fighting the war.

If I had a gripe, it might have been interesting to hear the views of veterans of the events described in the film. All the same, it is an unusual and different view of the wartime story and excellent value.