He describes Auschwitz as "hell on earth" and says he would lay awake at night listening to the ramblings and screams of prisoners.

"It was pretty ghastly at night, you got this terrible stench," he says.

He talked to Jewish prisoners but says they rarely spoke of their previous life, instead they were focused on the hell they were living and the work they were forced to do in factories outside the camp.

"There were nearly three million human beings worked to death in different factories," says Mr Avey. "They knew at that rate they'd last about five months.

"They very seldom talk about their civil life. They only talked about the situation, the punishments they were getting, the work they were made to do."