Austrian Jew Freddie Knoller was 11 when Hitler came to power. A 12-year ordeal followed, in which he fought for the French Resistance, took part in an Auschwitz death march and survived starvation. REBECCA LOWE finds out what sort of spirit it takes to endure so much.

Eighty-six-year-old Freddie Knoller's quiet, comfortable life in Totteridge is a far cry from the harrowing youth he endured under Nazi rule.

At his home, where he has lived with wife Freda for 56 years, he plays cello, entertains his children - and tours the country talking about a past in which none of these things were possible.

Freddie was born in Vienna on April 17, 1921, into what he describes as a "loving family". His book-keeper father provided a solid, middle-class upbringing for his three sons. It was, Freddie says, "a wonderful childhood". But a month before Freddie's 17th birthday, this childhood came to an abrupt end. In March 1938, Germany annexed Austria and enforced stringent anti-semitic laws. Freddie was sent to a refugee camp in Belgium by his parents, who told him they would find him "soon".

"But they never did," says Freddie. "They were gassed in 1943."

After two happy years at the camp, Freddie ran away to France to avoid the advancing Nazis. Here, despite the J' (for Jew) on his passport, he was sent to a war camp for enemies of the allies in St Cyprian, on the border between France and Spain, before escaping when the Germans arrived two months later. It was now August 1940.

Freddie fled to the south coast of France and then to occupied Paris, where he gained false identity papers and began a new life as a Frenchman called Robert Metzmer.

For a year, he earned a living introducing German soldiers to the red-light district in Montmartre, before an order from the Gestapo to work for them as a translator compelled him to break away and join the French Resistance.

"I was very happy," he says. "Instead of earning money from my enemies, I was able to fight them."

But Freddie's heroic efforts could not last long. Captured by the French in 1943, he had two choices: remain as Robert and give up the name of his Resistance group, or reveal his identity as a Jew. He chose the latter.

A few weeks later, Freddie found himself on a train to Auschwitz - a journey he will never forget.

"It was terrible. For three days we had no food," he says. "We had one bucket for sanitary purposes.

"It was impossible for all of us to sit down, so we half-sat on the floor and the others half-stood for four hours, then alternated. Four people died on the journey."

When they arrived, the men were sent to Auschwitz III, or Buna-Monowitz. Women and children were taken away in trucks and never seen again.

After having his hair shaved off and a number - 157103 - tattooed onto his arm, Freddie was finally given food: a bowl of soup. Many inmates couldn't take it, electrocuting themselves on the wire fence. But such despair never occurred to Freddie, who "had a different outlook and took things as they came".

A glimmer of hope that the end of their ordeal was near was October 1944, when Russian artillery fire was heard in the east. But for many, hope came too soon. Half of the surviving prisoners died in a freezing 15-mile hike from Auschwitz to Gleiwitz in January 1945: the infamous death march.

Freddie had become "accustomed to death". But nothing prepared him for the sight of Bergen Belsen. Sent there in March, he found 60,000 people abandoned by the Nazis, all slowly dying of typhus and starvation.

"There was no food left," he says. "I saw people cutting out flesh from bodies and roasting it behind the barracks. There were dead people everywhere."

Then, on April 15, a troop of British soldiers arrived with rice and hot milk. After seven years of suffering, Freddie was finally free.

By 1951, his life had transformed: he was married, living in Totteridge and enjoying the proceeds of a fashion business. But he says his "main mission" in life was to tell young people his story.

"I will never forgive the Nazis for what they have done. I will never forget. But the reaction from young Germans is that they want to know more, and it is important they are told."

u Freddie Knoller works with other survivors at the London Jewish Cultural Centre. Anyone interested in finding out more should visit www.ljcc.org.uk or call 020 8457 5000.