British survivors were among those returning to Auschwitz

With three British camp survivors and leaders from 35 countries they attended the ceremony to pay respects to the more than 1.1m who died there.

Auschwitz, the largest of the Nazi camps, was liberated by the advancing Soviet army on 27 January 1945.

Mr Straw said future generations cannot be allowed to forget the Holocaust.

'Never again'

"Auschwitz has become a symbol of suffering and persecution on a scale which is unique in human history," he said.

"It acts as a reminder to us all that the international community must work together to ensure that such atrocities can never be allowed to happen again."

I was just a skeleton in a ragged stripy uniform, but I was the only one in my family to survive British survivor Bob Obuscovski

The three British survivors of Auschwitz - Zigi Shipper, Bob Obuscovski and David Herman - said it would be hard to return to the place where so many were killed.

Mr Shipper, 75, from Stanmore in Middlesex, is taking his 16-year-old grandson to see the camp.

"If I can stand here today in Auschwitz with my grandson, then I can believe in miracles," he said.

Mr Obuscovski, 76, from Ilford, Essex, said he did not really want to go back to the camp.

He said: "People must never forget what happened here.

"In the end, I was just a skeleton in a ragged stripy uniform, but I was the only one in my family to survive."

Freezing temperatures

At least 1,000 survivors from many countries endured sub-zero temperatures at a snow-covered Auschwitz to take part in the outdoor ceremony.

It was held alongside the site of Nazi gas chambers.

During World War II 6m Jews were slaughtered as part of Hitler's "final solution", along with hundreds of thousands of others, from Roma gypsies, homosexuals and the disabled to the mentally ill.

Snow fell during the anniversary ceremony

More than 1.1m died at Auschwitz-Birkenau and its sub-camps. Of those, 1m were Jewish.

World leaders including Presidents Jacques Chirac of France and Vladimir Putin of Russia were also at the ceremony, as well as Germany's President Horst Kohler.

Prince Edward, Earl of Wessex, was accompanied by the British ambassador in Warsaw Charles Crawford and several members of the UK's Jewish community.

Earlier on Wednesday Prince Edward met relatives of 38 British prisoners of war killed in an air raid by American bombers on the Monowice labour camp, near Auschwitz.

Minister for Veterans Ivor Caplin MP unveiled a plaque to their memory. They were killed when an Allied bomber destroyed parts of the factory on 20 August 1944.