For years, Avraham Carmi felt a debt of gratitude to the Pole who saved his life. Like an angel the kind man swooped into his life, helped him in his hour of need and disappeared without revealing anything about himself.

Then one day - years later - Carmi found out his saviour's name, where to find him and the man's staggering secret.

Three days before the Nazis invaded Poland in 1939, 10-year-old Carmi, or Abrash Stohlbach-Weinberger as he was called back then, went with his mother from their home town of Krzeszowice to nearby Warsaw, which she thought was safer.

They stayed with his uncle, the manager of a Warsaw Jewish cemetery. They remained in his flat at the cemetery for three years, and then spent a month hiding inside a dug grave.

They subsequently spent seven months hiding in basements and underground bunkers in the ghetto, until in April 1943, at the height of the Warsaw Ghetto Uprising, soldiers discovered them and took them to Treblinka.

I don't think I felt anything. If you haven't eaten for five days you don't think

Hearing Carmi recount his story is almost like watching a film. He lived to tell the tale so you know there is a happy ending, and there is a sense of what twists and turns may be coming, The gripping details emerge one after the other.

As he sits on the sofa in his home at the agricultural school near Tel Aviv where he used to teach, Carmi speaks softly but confidently, and breaking off to check that the cleaner has a snack and that his wife, Rivka, is OK.

A combination of his good fortune and his jolly personality means he tells his story with enjoyment and even a touch of excitement. A piece of paper which reminds him of the important dates has some water stains on it. "It's not tears, it's rain – don't present me as a nebech," he requests.

A few days after being rounded up, Carmi and his mother were taken from Treblinka to the Budzyn labour camp in Eastern Poland, and separated from each other by the SS, never to meet again. Today, he recalls this with inevitable sadness, but asked how he felt back then he responds: "You want to know the truth? I don't think I felt anything." He elaborates: "If you haven't eaten for five days you don't think. You know what I thought? 'A bit of water, not even bread, just some water.'"

By this point Carmi was 15, and was shipped off from the camp most days to work as a slave labourer in an aeroplane factory. He had to paint aeroplane wings, and the regular use of acetone-based colours was causing a major deterioration in his health.

The factory was managed by Poles, and one day - out of the blue - a foreman approached him and said he wanted to "do something" for Carmi. With an audacity that bemuses him today, he asked the foreman to go to the Jewish cemetery in Warsaw and retrieve his mother's jewellery, which she had buried.

The next time the foreman saw him, he produced a loaf of bread. Carmi hid it under his shirt, "together with the lice" and later in the day, on his bunk, shared it with close friends. "What do you do to cut bread when you don't have a knife? We tore the bread, and as we did, out of the middle fell the jewellery."

He used his mother's treasures as currency to keep himself alive through the war. He bartered them with Polish workers for food. By the time he had sold everything, he was working as a domestic servant in the home of a Nazi apparatchik where he ate adequately - he was responsible for feeding household scraps to the pigs and took the choicest pieces for himself first. Of the cemetery stash only one thing remained - the purse that held the jewellery.

He told the lady of the house about it. "She said 'what do you want for it?' I said: 'Make me apple kuchen'. She didn't know how to make it, but I'm a good boy and I explained how my grandmother did it - she made the dough, put the apple in, and then she topped it with egg. She said 'Ok, show me the purse and I'll make you the kuchen.' I said: 'Make me the kuchen and I'll show it to you.'"

They made a deal, and the next day Abrash dropped the purse in to one boot in the entrance to the house, and collected a kuchen from the other. He inhales happily as he tells this part of his story. "The smell was, for me, more than words - the smell remains over time. It's freezing and you're on the bunks, having urinated and excreted with 1,000 people and you no longer have a name, but then comes a smell that you remember over time."

Abrash made it to the end of the war, and in October 1945, undertook an epic journey. It took him through Switzerland and France, and, via a British detention camp for illegal immigrants, to Mandate Palestine and Mikveh Israel, the agricultural school where he lives today. Having renamed himself Avraham Carmi, he became a student, then a teacher, deputy head teacher and eventually head teacher. He later became an inspector for Israel's teacher training colleges, and retired in 1993.

At a book launch in 1963, he bumped in to Yurek Polansky, a friend from his time hiding out in Warsaw, who had become a kibbutznik.

Polansky managed to stay in Warsaw throughout the war, and he met Carmi's saviour the day he came for the jewels, and helped him to locate them.

He had also learned the saviour's secret - he was actually a Jewish man named David Lieberman who looked Aryan and used his non-Jewish appearance to survive the war.

Lieberman, it transpired, had ended up in Tel Aviv, where he ran a garage. The next day Carmi went there early in the morning and waited for him to arrive and open up.

Carmi told Lieberman that he was the teenager whom he saved, and thanked him. The meeting, while poignant, was quite subdued. Carmi says that while one would envisage it to have been a gushing emotional reunion it was not - he was rather unsure of how to express his thanks and Lieberman was unsure how to receive him. "What was I able to give him to express my thanks? A flower? A piece of cake?"

Lieberman is not traceable today. If he were alive he would be around 100 years old. They met on a handful of occasions, including at Polansky's 75th birthday party, where all three men told the story of the life-saving jewellery stash as they remembered it. But they did not become friends. "If I saw him time after time I would be living back in the camp," reflects Carmi.

But he regards Lieberman as one of the "36" - the 36 saints of Jewish mysticism - and an agent of God's lighter side.

With a Jewish Aryan-imposter, a jewellery sandwich and the wife of a Nazi apparatchik baking kuchen to an old Jewish recipe, Carmi says that his story proves that "the Master of the Universe has a sense of humour."