Jeremy Isaacs and David Elstein: how we made The World at War

Jeremy Isaacs, producer

One of our best researchers, Sue McConachy, had nightmares about some of the things the Nazis she interviewed told her. She was blond, blue-eyed and fluent in German – and she gained the trust of an SS commander who told her, his hand on her knee, that she was the sort of stock SS men liked to breed from. She even managed to interview Hitler's secretary. It took a whole year of persuasion. Giving some of the Nazis a voice was quite hard to stomach: at least one SS soldier we found was completely unrepentant.

I had asked Noble Frankland, director of the Imperial War Museum, to name 15 military campaigns that could not be omitted, and decided to use the other programmes to examine the impact of the war on civilians. I wanted to hear not just the voices of people who dropped the bombs, but also those they targeted.

Carl Davis agreed to compose the score and at first rapped out a military march on the piano, but I needed music to convey, above all, human endurance. Carl delivered it. Laurence Olivier was keen to do the narration, but he was unhappy with the first film we showed him – the fall of France. He found our clipped, matter-of-fact script uninteresting and wanted out. I went to his agent, who promised me the contract would be honoured, and said: "Have you told him he's wonderful?"

We had two excellent researchers digging through archives to find fresh film. Newsreel alone is no good because it's already been edited and is propagandistic in tone. A BBC cameraman who had filmed on the Dunkirk beaches told me that nothing he had shot there was ever used because it showed an army in defeat. But the most remarkable raw footage I saw was found in German archives. It showed a handful of German soldiers with the population of a Russian village assembled on one side of a bridge, divided into men and women. They were sent off in different directions in tears – they knew they'd never see each other again.

David Elstein, producer/director

Jeremy asked me to direct three of the episodes because I was a historian with some expertise on the Battle of Britain. Despite my knowledge, it was fascinating to discover from a Luftwaffe commander that the Battle of Britain, regarded by the Allies as a turning point in the war, was of little significance to the Germans. They saw it as a rehearsal for an attack on the Soviet Union. Astonishingly, the commander recalled that at one point, when the pilots were gathering to launch another attack, Hitler called them off to target the Soviets.

The biggest challenge was to carve up the war into 26 one-hour episodes. On reflection, we were too focused on the west and not enough on eastern Europe and the far east. We had to tell a complex story as clearly as possible, in a way that would appeal to a mass audience. Previous documentaries had been along the lines of General So and So takes you through his great battles. It was generally a hierarchical, over-didactic view. Jeremy avoided a chronological account of military action – he wanted to examine the experience of war from all perspectives, to convey to the next generation the impact it had had on people's lives.

My researcher, Isobel Hinshelwood, was a persuasive, canny Scot who went drinking in the pubs of London's East End to recruit people who remembered the Blitz. We assembled them all in one pub and asked them to tell their stories together, because it was the collective experience that defined the Blitz.

A decade earlier, the BBC had run an ambitious series, The Great War, that had been criticised for inauthenticity. So we commissioned an archive expert to examine every piece of film we unearthed. One of the funniest moments came when he watched a rough cut of our Battle of Kursk episode. He said it didn't look right and, sure enough, we found that, because little of the original action had been filmed, the Russians had restaged it for their archives, in better weather.

Having Olivier as narrator gave the series great credibility. He was very professional and dispatched his part in double quick time, in order to get out of the tiny recording studio. The only problem was persuading him not to call Stalin "Staleen".

One afternoon, I was showing a rough cut to Jeremy in which an interviewee – who had been an MP and an army major – recalled the botched military campaign in Norway. He said the army had improvised the campaign with the wrong equipment and in too much haste. Jeremy stopped the machine and asked why I had considered this important enough to leave in – because what was so bad about improvisation? I had to explain that improvisation can work well in television, but in military operations it is not a good idea.