A Holocaust survivor whose life was saved by a Catholic priest during the war will visit the Vatican next month to thank the Pope.

Joseph Szlezinger was hidden in a Belgian convent and his mother Gita lived for 18 months in a basement after the priest, Father Clement, agreed to protect them from the Nazis.

The 74-year-old Finchley Synagogue member wrote to the Vatican in August, explaining how Father Clement had come to his family’s rescue during the Shoah. But the father-of-three was stunned to receive a reply inviting him and his wife Kathrin for an audience with Pope Benedict XVI .

Mr Szlezinger’s father, Samuel, was deported to Auschwitz in 1942, prompting his mother to send the young Joseph to live with a friend.

But when the friend later asked for a lump sum payment for hiding him, Gita took her son and ran away.

He recalled how, in desperation, his mother went with him to a local Catholic school and asked to see the headmaster — Father Clement.

“She told him we had nowhere to go. But when he saw her Star of David inside her lapel, he said he couldn’t help, it was too great a risk. She said to him: ‘I’m in the house of God and there’s no way I’m leaving’.”

Father Clement was already hiding around two dozen Jewish children in the convent and eventually agreed to protect Joseph. The seven-year-old was given the name of Joseph Dupont, a Belgian boy who had been killed in an air raid, and the priest provided him with false papers.

The priest had a friend who was a policeman. “He took my mother to the man and he put her in the basement. She never came out for about 18 months. When she emerged she was nearly blind.

“Every week Father Clement went to visit her and took a parcel of food in his cassock. I never even knew she was there.” He lived a relatively comfortable life during his two years in the convent in Chimay, southern Belgium.

“I had a very good time during the war. In the back of my mind I knew I was Jewish but we went to church every morning and had religious classes every day. When you think your father is not coming back and you are wearing a yellow Star of David, you learn very quick.”

At the end of the war, Father Clement took him back to Brussels for an emotional reunion with his mother. “The first few weeks I really didn’t know who she was. I was calling her ma soeur, my sister.” There was also the uncertainty about the fate of his father.

“After the war they brought back the people from Brussels who had been in Auschwitz,” explained Mr Szlezinger, his eyes welling with tears. “They used to bring them to the square and people would go and check whether they recognised anyone. This was the worst thing for me. Every Sunday I would go and look and come back to the house and my mother would ask me who had been there. My father was never there. She would say: ‘See Joseph, we have no mazel’.”

They left Belgium in 1952, moving to Britain and settling in Chigwell, Essex, where Mr Szlezinger set up a property business. He now lives in Hampstead.

His visit to the Vatican will, he feels, give him closure: “I sent the letter because I was going to Rome and I thought this was my opportunity.

“Despite what everybody says about the Catholics, they saved my life. I owe it to Father Clement to say thank you.”