Claus von Stauffenberg: the true story behind the film Valkyrie, starring Tom Cruise

Just before 1pm on a boiling hot day in 1944, a 10-year-old boy sat down to lunch at a grand country house in the hills near Stuttgart. An earnest young man, and the heir to one of Germany's most noble families, Berthold von Stauffenberg was in awe of the Nazi regime and talked excitedly about joining the Hitler Youth. But, 800 miles away, his father, Claus, had other plans. A colonel and a trusted member of the Führer's inner circle, he was, at that precise moment, trying to kill Hitler with a briefcase full of explosives. 'It was the closest anyone came to killing him,' says Berthold, now 74 and a fierce guardian of his father's legacy. 'He did what he did, and sacrificed his life, through sheer moral duty.'

Claus von Stauffenberg was a 'good German' amid a nation of demonised villains. An extraordinarily brave soldier and a charismatic leader, his attempt to kill Hitler on 20 July at the Nazi leader's eastern HQ - known as the 'Wolf's Lair' - will receive the Hollywood treatment in a new film, Valkyrie, starring Tom Cruise and Kenneth Branagh, being released next year...