The German who bombed Hitler: When a plot to kill Hitler failed, 50 years ago, retribution fell swiftly and brutally on the plotters and their families. But a few survived. Steve Crawshaw hears their stories

Hans Christoph Freiherr von Stauffenberg was at the theatre, listening to a performance of The Marriage of Figaro, when he heard the news of the event that has become a symbolic landmark in German history. 'They came on to the stage, and said: 'Something terrible has happened. There has been an attempt on the Fuhrer's life'. Then, the opera continued.'

When Stauffenberg, an aristocratic lance-corporal ('I didn't want to be an officer in Hitler's army'), got back to his barracks that evening, 50 years ago this month, his commanding officer told him that that he should 'report for duty, as usual'. Still, he did not realise what had happened. 'I thought: why should anybody expect me not to report for duty?'

Only the next morning did he discover the truth: that his own cousin, Claus, was at the centre of the plot, which failed - just - to end the Hitler regime. Claus had been executed by firing squad a few hours after the bomb he had planted exploded at the Wolf's Lair, Hitler's headquarters in East Prussia, on 20 July 1944. 'Long live Germany]' he shouted, as the fatal bullets were fired.

When the Gestapo came to take Hans Christoph away the next morning, he burnt a couple of letters before leaving. But he remained surprisingly calm. Now aged 81 (though he looks years younger), he remembers: 'They took me into the cellars. I was waiting to see if they'd put the pistol to my head. But they didn't. They bolted the doors of the cell. I looked to see if there was blood on the walls. Then I just fell asleep, on the hard wooden bench.'

Hans Christoph von Stauffenberg was arrested not because the Nazis had any reason to suspect him. Indeed, he emphasises that he was never an active member of the resistance - 'I was afraid of what I might say if I was tortured.' Instead, he was taken in by the Gestapo as part of the Nazis' revenge for what Claus had almost succeeded in doing.

All immediate relatives of Claus von Stauffenberg, and of the other main plotters, were rounded up in the days and weeks immediately after 20 July. This was Sippenhaft, 'family responsibility', whereby everybody in the family was to be punished. Hans Christoph regards himself as lucky: he was released after a couple of months. Claus's widow, Nina, who is still alive, remained in the camps until the end of the war; Nina's mother, a defiant spirit who told the Gestapo that she was proud of her son-in-law, died there.

Even the children were not spared. Claus's eldest son, Berthold - then aged 10, and now a general, responsible for Germany's Southern Command - heard a snatch of news on the radio on the evening of 20 July. But nobody would tell him what it meant. The next day, Berthold's great-uncle (later hanged), took the children for a walk. 'He told us about his travels. He told us about hunting big game in Africa. Then, in the afternoon, my mother told us it was our father who had laid the bomb. I asked: 'Why?' And she said: 'Because he thought it was the right thing for Germany.' '

The Nazi machine began to take its revenge. Only days after the failed plot, the children were woken to be told by their nanny that their mother had been taken away. The Gestapo sealed up rooms in the family property at Lautlingen. Some weeks later, the children - Berthold, eight-year-old Heimeran, six-year-old Franz Ludwig and three-year-old Valerie - were themselves taken away. A children's home was specially emptied for them, and for the children of others involved. Even the children's names were taken away from them: officially, the Stauffenberg children were now called 'Meister'. Berthold today speculates that this particular name was chosen because the children were due to be adopted into a Nazi family of that name, but nobody now knows the real reason.

Meanwhile, Nazi justice began to take its course. The main plotters were shot, together with Claus Stauffenberg, on the first night. Many others were hanged, in the weeks and months to come, after being horribly tortured.

Hitler spoke of a 'small clique of ambitious, criminal, stupid officers without consciences' as being responsible for the attempt on his life. In reality, it is remarkable just how many people were directly or indirectly involved in attempts to get rid of Hitler. An entire military network was in place, together with a list of names and cabinet posts for the proposed civilian government. Hitler's opponents waited, dreamed, and planned.

Within that opposition network, Philipp Freiherr von Boeselager is one of the tiny number of those who - because the Nazis never discovered his connection with the opposition - is still alive. Part of Boeselager's name is itself a pointer to a notable feature of the opposition to Hitler at that time. Freiherr means baron. Claus von Stauffenberg was a Graf, or Count. This resistance movement was unambiguously led by the social and military elite.

Boeselager, who was an aide to one of Hitler's commanders, Field Marshal Gunther von Kluge (who committed suicide after the assassination attempt) now talks wistfully of the missed opportunities. The occasion where Boeselager and his friends came closest to success was on 13 March 1943. A planned shooting of Hitler during a meeting was called off at the last moment. Instead, a bomb was put on to a plane that Hitler was to travel in. But it failed to explode, apparently because of the cold. The 'two bottles of schnapps', as the bomb package had been described, quickly had to be rescued when the plane arrived at its destination.

Boeselager was also involved in the supply of explosives to Stauffenberg. He worked for an 'explosives research' team which was set up partly to give cover for gathering bomb materials. 'One day in spring 1944, my brother rang me, and said: 'You must deliver some of your explosives.' '

When Boeselager arrived with his deadly cargo - 'I had English explosives, because those were the best' - the man he was supposed to deliver it to (Helmuth Stieff, executed August 1944) was in a meeting, so Boeselager went to watch a film to avoid drawing attention to himself. 'They were showing a comedy. But I didn't see much. I had to be careful that people didn't trip on the suitcase.' Finally, he got to see Stieff. 'I said: 'I'm supposed to give you a suitcase.' He said: 'Thank you.' And that was all.'

Initially at least, some of Hitler's critics were motivated partly by the belief that he was conducting the war badly, rather than a feeling that the war was itself wrong. But that changed. Helmuth Graf von Moltke (executed, January 1945), a friend of Hans Christoph von Stauffenberg, was one of the leaders of an occasional discussion group at his estate at Kreisau - in effect, an informal opposition. When Moltke introduced Hans Christoph to Peter Graf Yorck von Wartenburg (hanged, August 1944), it became clear that Yorck was worried that there was a disproportionate number of Grafen, Freiherren and von's in the opposition to Hitler.

As he sits in his 18th-century manor house in the south German countryside, Stauffenberg recalls: 'We had hardly met. He said: 'Do you have contacts with the workers' movement?' ' A startled Stauffenberg replied that he did not. Yorck insisted: 'If we are just a ruling class, we will have failed completely. That's why the Nazis came to power. It was the workers who were promised a better life, not us.' Stauffenberg admitted that perhaps he was 'not the right telephone' if contact with the workers was sought.

However Hans Christoph provided a crucial link to Claus, via Claus's brother Berthold (hanged, August 1944). Claus's first response to these soundings was unpromising. By 1943, however, he came to be at the forefront of the resistance, while keeping his position within the Nazi elite.

Claus became closely involved not only with the plot on Hitler's life, but also with the plans for creating a new government after Hitler's fall, which would bring together leading conservatives such as Carl Friedrich Goerdeler (hanged, February 1945) and leading Social Democrats such as Julius Leber (executed, January 1945) under a single political roof.

But for two circumstances, Stauffenberg's assassination attempt would have succeeded. Lack of time meant he was able to place only one bomb, not two. He was interrupted at a crucial moment, and the planned meeting with Hitler had suddenly been brought forward by two hours. Second, the briefcase containing the bomb, which Stauffenberg left under the table close to where Hitler was sitting, was near a massive oak support which protected Hitler from much of the force of the explosion. He was able to leave the room almost unharmed, except for a few grazes.

Meanwhile, despite the failure of the plot, whole mechanisms had been set in motion, which were only halted with difficulty. Thus, Philipp von Boeselager describes an 'unbelievable' 120-mile ride in 36 hours, with 1,000 horsemen under his command, to reach an airport in western Russia from which he was due to fly to Berlin to help to install the new government. Boeselager suddenly received the coded message: 'All back into the old holes]' The the plot had failed.

During the return journey, there was a moment when the secret purpose of the ride came close to being exposed. 'It was a beautiful night. Whenever there is a warm summer's night, like we have had recently, I still think of it. It was very quiet. You just heard the squeaking of the saddles and the grating of the horse's jaws. And then, suddenly, there was a bang.' One of Boeselager's closest comrades had been killed instantly as he rode over a mine. But grief had to take second place because one thing mattered above all: Boeselager had to get at the strategic map of Berlin in the dead man's pocket. If found, it would expose the connection to the plot and the planned takeover of key buildings in Berlin.

Among the Western Allies, there were expressions of relief that the plot had failed. After all, the argument ran, it was simpler if one knew that one was dealing with Bad Germans.

The 50th anniversary of the remarkable events of 20 July have been the occasion for an outpouring of commentaries in the German press. 'Unhappy the land that has need of heroes', Brecht wrote. Unhappier still, it could be argued, is the land that needs heroes, and finds none. In recent weeks there has been considerable controversy within Germany about a museum of the resistance in Berlin, and about the inclusion of pro-Moscow Communists - including loathed figures such as Walter Ulbricht, who later ordered the building of the Berlin Wall - alongside Stauffenberg and other members of the 'true' resistance. Claus von Stauffenberg's son, Franz Ludwig, has clashed fiercely with the museum's curator over the issue.

Eventually, that controversy will fade. But the tangled legacy of 20 July will remain. Hans Christoph points to a psychological barrier that the opponents of Hitler had to cross. 'We couldn't want our own country to win. We knew that if the Nazis won, it would be the end of the West. And yet, it's very difficult to want one's own country to perish.'

Boeselager echoes that view. 'The French resistance were acting for their own country. But we were acting against our leaders. That was difficult. Only gradually do you accept that it's not your state - but a criminal state.'

Their plot failed and Stauffenberg and his comrades died, but they stand as a reminder for Germans themselves, as much as for the rest of the world, that not all Germans were ready to accept the madness.

(Photographs omitted)