Assigning a star rating to this documentary would be unthinkable. Everyone from the most digitally-distracted teenager to the oldest Holocaust denier should see Night Will Fall. Without the colour and glittering cast of a Hollywood Shoah production such as Schindler's List, this is a film some will only watch under duress.

But being reminded of what the Jews endured in the camps is crucial at a time when antisemitism is once again so rife.

It fell to Act of Killing director Andre Singer to make this film, which tells the story of, and contextualises, a lost documentary - German Concentration Camps Factual Survey - which was shot at the end of the war by soldier-cameramen who were part of the liberation forces.

It was Sidney Bernstein, latterly assisted by Alfred Hitchcock, who produced the film, intending for it to be seen by anyone in doubt about the Nazi atrocities - notably the German people. Bernstein knew there would be non-believers, even as he watched skeletons of all sizes being dragged into mass graves at Bergen-Belsen, Auschwitz and Dachau. So he demanded close-ups of every detail, be it the mountains of discarded spectacles to the haunted faces of the starving survivors.

To this horrific footage, Singer has now added interviews and moving testimonies from soldiers and some survivors, among them Anita Lasker-Wallfisch, who was at Auschwitz.

For Jews, this is anguished viewing

For Jews, Night Will Fall offers nothing but anguished viewing, compounded by the fact that the original documentary was never finished. More significantly, it was never shown to those it should have reached, for in the spirit of post-war diplomacy, Bernstein's project was censored and ultimately shelved to spare the feelings of everyone. Everyone except the six million, that is.