Britain's World War II films were more than just propaganda

In most of the important matters – arming its soldiers, arresting its dissidents and invading other countries – the outbreak of the Second World War saw Nazi Germany with a seemingly insurmountable head start. The same went for brainwashing its inhabitants. Joseph Goebbels and his lavishly financed Department of Film had been pumping out propaganda since the Reichstag burned down in 1933, preparing its citizens for genocide, global domination and the general triumph of the will. Much of it was vile, of course, although Leni Riefenstahl is arguably the most talented woman ever to direct a film (which possibly makes her viler still).

Britain's answer to Riefenstahl, in artistic ability at least, was Humphrey Jennings – the East Anglian poet of the Thirties documentary movement. Jennings' great trilogy of war films – Listen to Britain, Fires Were Started, A Diary for Timothy – stand above and apart from the rest of the propaganda produced by the Ministry of Information's Crown Film Unit. To quote the film historian David Thomson: "[Jennings was] a true war artist in the way that Henry Moore's drawings in the Underground and Evelyn Waugh's Sword of Honour trilogy transcend war and reassert the primacy of the human imagination."

But enough about art and the human imagination. We can admire Jennings' deeply poignant documentaries today – as indeed, with more discomfort, we can appreciate Riefenstahl's demented but beautifully framed hymns to health and efficiency. This flowering of the documentary form was, however, a by-product of the more utilitarian output of the Crown Film Unit – documentaries, comedies, cartoons and dramas, long and short, that told you what to do, and what to avoid doing. Grow your own, keep mum, make do and mend... most of these almost 2,000 productions (what would now be known as public information films) are today stored in the vaults of the British Film Institute in London. A select few of them can be seen in a new TV series, Home Front Britain, starting next week (11 September) on the Discovery channel. And what an intimate and revealing picture they provide.

"This is what the characters in Dad's Army would have seen at Walmington-on-Sea in the cinema," says Jan Faul of the BFI, who assisted in the making of the series. "The cinema was the only visual record of what was going on – that's why the propaganda machine with the Ministry of Information was so important to the war effort. It went all around the country; everyone was looking at this stuff and learning from it."

The Second World War was, when filmed propaganda came into its own, one of the reasons why the Government was determined to keep the country's 4,000 or so cinemas open. First World War propaganda had mainly been waged by poster art – indeed, it was Hitler's belief that Great Britain's poster campaigns had helped win the war that spurred him on to create Germany's own formidable propaganda apparatus. Not that the British were entirely slow off the mark in 1939. While the Ministry of Information first officially manned its desks on Monday 4 September, it had secretly been planning for this moment since 1935. And for film propaganda, the Ministry looked to the talents of the GPO Film Unit, restyling it The Crown Film Unit.

One of its earliest films, made after the fall of France in June 1940, with the suitably sombre title of Britain at Bay, betrayed the Crown Film Unit's antecedents in the GPO Film Unit – the division of the General Post Office that nurtured many of the socially committed artists of the British documentary movement. The GPO Unit's most enduring film is Night Mail, with music by Benjamin Britten and words by W H Auden. Britain at Bay was written and narrated by J B Priestley and ended with the writer reciting Churchill's rallying "We will fight them on the beaches" speech. Stirring as it is, even at this remove, it's the smaller, more practical films that are the more fascinating.

Take for example Ordinary People, made at the height of the Blitz, with – as the title alerts us – ordinary people playing themselves, going about their lives during the Blitz. Such films seem to be a vindication of John Grierson, the austere Scottish father-figure of the Thirties documentary movement, and his manifesto "of opening up the screen on the real world... documentary can achieve an intimacy of knowledge and effect impossible to the shim-sham mechanics of the studio, and the lily-fingered interpretations of the metropolitan actor."

Shim-sham or not, the public still wanted their studio confections – and a succession of drama and comedy shorts starring popular actors of the day demonstrated how careless talk costs lives (sailor John Mills is overheard telling his travel plans to his girlfriend in All Hands), how to deal with an incendiary bomb (or not – bumbling paterfamilias Will Hay's wife and daughter save the day) and how to accept women in the workplace (chauvinistic factory owner Alastair Sim only coming round to the idea after his daughter takes a job at one of his lathes).

"People enjoyed them because you had recognised stars," says Faul. "Whether it's comedians of the time doing funny little spoof flashes, or Olivier or Michael Redgrave... There's one film called There's a Future in It, with Ann Dvorak and Barry Morse, about a girl who falls in love with a bomber pilot. Morse was later to be in The Fugitive. You keep coming across actors who would one day be famous."

Stories could be just as effective as stars. Racy little melodramas with fantastic titles like Miss Grant Goes to the Door, in which two elderly sisters living in a remote cottage get the better of fifth columnists, carried explicit instructions on what precautions to take in the event of invasion ("keep the man talking; if he's a German he'll give himself away eventually").

And there's a surprisingly hard-hitting film about VD, Love on Leave, which peacetime censorship would surely have prohibited but which is honest enough to shame the obscure Aids adverts put out four decades later by the the Central Office of Information.

But it's the documentaries that are more poignant and intriguing in their glimpses of wartime Britain – the bad teeth and long-vanished accents – and the details of life during Our Finest Hour. We are used to images of city children being evacuated, but another documentary, The Village School, shows how rural schools were stretched by evacuees, operating a double-shift system whereby locals were taught in the morning and newcomers in the afternoon. Those despairing of today's rigid primary school curriculums will feel pangs at the sight of pupils involved in such activities as knitting socks for soldiers.

If the British propaganda film-makers of the period had to stretch their creative powers to the maximum, then that is surely only an illustration of the differences between making propaganda in a democracy and making it under a dictatorship. It's the difference between being deftly persuasive and lazily indoctrinating. And, of course, hateful. The message of Fritz Hippler's The Eternal Jew was, or should have been, all too clear to the outside world. British propaganda was aimed overseas to either encourage America to join the war or, once that was achieved, to instruct them in life over here. One such short warned GIs not to get the wrong idea if a Londoner called him "darlin'".

The films aimed at British audiences weren't only shown in cinemas, but also in factories and social clubs. Local audiences were addressed with increasing frequency, says Faul. "Cinemas would have films of local councillors appealing for people to look after, say, single female neighbours, or to dig allotments. We've got one called Greenford and Northolt Dig for Victory (a 1942 film about Ealing Borough Council's allotment scheme for the Dig For Victory campaign), introduced by a local councillor. People embraced it locally after seeing what went on nationally."

And while there might have been a paternalistic tinge to much of this output, there is also a remarkable amount of good humour and inclusivity. "I think Harry Enfield did these sorts of film a disservice with Mr Cholmondley-Warner," says Faul. "People have that impression of scratchy film with a man with a pipe pontificating at you. I think the propaganda films played an important role in drawing everybody together. There was a common purpose in these films, and it made everybody feel they had a role to play."

'Home Front Britain' begins on the Discovery Channel on 11 September