One of the last remaining survivors of the Nazi concentration camp at Sobibor told the trial of John Demjanjuk yesterday that he still had nightmares about his time there.

Thomas Blatt, 82, whose parents and brother were among the 250,000 people estimated to have perished there during the Second World War, said: "I go there in my dreams. They are so real. In them I am still there. I can't get it out of my head. This is the price I paid for getting out."

He told the court in Munich, southern Germany that he was unable to place Demjanjuk, 89, at the camp in occupied Poland, but that "only Ukrainians like Mr Demjanjuk guarded us".

There are no living witnesses able to positively identify Demjanjuk, but the prosecution says it has an SS identity card proving he was at the Trawniki training camp for guards and that he was transferred to Sobibor.

Prosecution lawyers are using testimony from survivors to prove that if Demjanjuk was a guard at the camp, then he would have played an active role in the mass killing that took place.