On a dreary October afternoon in 1944, the notorious Josef Mengele, often referred to as the Angel of Death, made his way into Block 11 of the Auschwitz-Birkenau extermination camp. His presence there was not out of necessity, but rather a chilling commitment to the grim duties he had embraced, taking a twisted pride in the suffering of those whose fates he had already sealed.

Inside the stark, wooden confines of the barracks, roughly 800 Hungarian Jewish boys, aged predominantly between 13 and 17, were packed tightly into a space measuring just 116 by 36 feet. The bunks had been removed following a scarlet fever outbreak, which had tragically led the previous occupants to their deaths in the gas chambers.

Fear and a morbid curiosity gripped the boys, who hadn’t eaten for almost two days. Many succumbed to tears, while others clung to fervent prayers, hoping for some form of salvation.

Mengele’s appearance was meticulously crafted to instill fear and exert dominance. His imposing posture, coupled with a black leather overcoat, immaculate white gloves, and gleaming boots, left an indelible impression on all who encountered him.

Everything about Mengele, from his haughty demeanour to his black leather overcoat, pristine white gloves and highly polished boots, was designed to intimidate and impress.

It was just another day in the life of this infamous SS physician who oversaw the extermination programmes. The boys were merely a means to an end, in fulfilling a quota of a minimum of 5,000 deaths a day.

During the selection procedure, deciding who would be next for the gas chamber, Mengele’s fingers moved from the knuckles upwards in a contemptuous flicking motion.

The ritual was hypnotic, theatrical, dehumanising and deadly. Mengele used these selections to seek out raw material for his research into racial purity – personally administering deadly injections of phenol, petrol, chloroform or air.

Josef Mengele, the Angel of Death, used inmates at Auschwitz for his research into racial purity – personally administering deadly injections of phenol, petrol, chloroform or air

A like-minded Nazi guard was Irma Grese, a notorious sadist and sexual pervert who was alleged to have had an affair with Mengele

A like-minded Nazi guard was Irma Grese, a notorious sadist and sexual pervert who was alleged to have had an affair with Mengele. She would slash women inmates across their breasts with a cellophane whip or beat them with a rubber truncheon and frequently sent healthy prisoners to the gas chambers. She also enslaved attractive young inmates, sexually abusing them before becoming bored and despatching them to their deaths.

The date of the boys’ planned deaths, Tuesday, October 10, 1944, had been set – Simchat Torah, one of the most festive days of the Jewish calendar. The youngsters were among an estimated 424,000 Hungarian Jews deported between May and July 1944 to Auschwitz-Birkenau after Hungary passed anti-Jewish laws as part of its alliance with Hitler.

On that fateful day, Winston Churchill was in Moscow, confirming the Soviet Union’s entry into the war against Japan, and dividing up the Balkans with Joseph Stalin.

Although the boys’ deaths were seemingly to be a formality in a killing field where around a million Jews and another 120,000 ‘undesirables’ spent their final moments, remarkably, 51 were reprieved. This was the only recorded instance of a group of Jewish inmates being removed from a gas chamber.

My new book, written with Naftali Schiff, a leading collator of Holocaust testimony whose work has been authenticated by eminent Holocaust scholars, tells that story using interviews with the survivors, of whom Hershel Herskovic, now 98 and living in London, was believed to be the only one still alive until Mordechai Eldar, now 95, was discovered living in Israel. That something so life-affirming, so miraculous, as this story of survival can happen amid such evil is sobering and inspiring. It begs the question what we, in a subsequent generation, would do with a second chance at life.

The boys were terrified, because they knew the subtext of being ordered to congregate for a headcount on the evening of October 9. Mengele had their identity cards stamped with a solitary German word, ‘gestorben’. It meant dead, or died.

To reinforce the point, Mengele’s clerk scored a line through a ledger containing their names. Yaakov Weiss, who though only 13, had emerged as a natural leader of the boys, thought to himself: ‘We are finished. We have been crossed off the list of the living.’

The entrance gate of Auschwitz concentration camp that reads ‘Arbeit Macht Frei’ (Work Sets You Free)

Auschwitz commandant Richard Baer, Josef Mengele and Rudolf Hoess, former commandant of the camp, in 1944

Wailing gathered in volume. Dressed in striped uniforms and wooden clogs, everyone was waiting for the summons that came at noon the following day, when guards burst in screaming, ‘Raus, raus!’, an order amplified by indiscriminate use of whips and sticks.

Marched to Crematorium 5 by 25 bayonet-wielding SS men, the boys were stripped and waited several hours before being herded into the gas chamber.

The Sonderkommando – Jewish prisoners who postponed their own execution by burning corpses and spreading ashes – had prepared the chamber, clearing bodies from the previous round of killings, and closing the air vents. Tins of Zyklon B had arrived in a truck with deceptive Red Cross markings five minutes after the boys entered the disrobing room.

The gas chamber’s heavy front doors – hermetically sealed by felt – began to close, snuffing out the last of the light. Eternal darkness was about to descend.

Mordechai Eldar, then 14, was among those selected to die. He steeled himself for what he said was ‘my final day’, consoling himself that he would be reunited with his parents. Then three German officers, including another infamous SS doctor, Heinz Thilo, arrived on motorbikes and ordered that the doors be re-opened.

Unlike those whose desperation led them to surge towards fresh air, Yaakov Weiss held himself back as the guards created a corridor, pushing the boys towards one wall.

Older occupants of the chamber were herded the other way.

Yaakov’s brain was suddenly racing. He later recalled: ‘Were the guards simply looking to see whether the youngsters were healthy enough or strong enough to be gassed? Or didn’t they have enough gas for us? Did they want to use dogs on us instead? Were they taking us out to shoot us? It’s only a matter of how they want to dispose of us.’

SS-Obersturmführer Johann Schwarzhuber, who oversaw the gassing programme and would later be executed for war crimes, grabbed the first boy by the shoulders, felt his biceps and ordered him to do ten knee-bends and sprint to a nearby wall and back.

Seemingly satisfied with this illustration of his fitness, the Nazi turned him around, and pushed him away, to form a new line for those reprieved, on the right.

Sruli Salmanovitch, a Transylvanian boy, was next to be inspected. He was relatively small. The German guard asked him his age. ‘Nearly 100,’ the lad answered.

He was to pay for this defiance with his life. The SS officer shoved him to the left and led him to the gas chamber, screaming: ‘You pig! Is that the way to speak to me?’

Children pictured behind a barbed wire fence after the liberation of the camp 

A 15-year-old Russian inmate, Ivan Dudnik, is helped out of Auschwitz by rescuers

Nachum Hoch, a boy from an Orthodox Jewish family in Transylvania, was asked to do the set of exercises that would decide whether he had a future. He did enough to convince the SS officer of his usefulness and stumbled towards the first boy to be saved. There seemed no obvious pattern in those who were given an apparent reprieve.

The boys had long since been stripped of their dignity. Those who had been rejected were starting to understand the probability of their fate; they began to cry until they were beaten into relative silence. This selection process was no act of mercy, though it seemed apparent that some of them might survive.

Suddenly, SS-Obersturmführer Schwarzhuber’s tone darkened. He motioned in the direction of those condemned on the left-hand side and laced his words with menace: ‘Throw them into the oven.’

The gas chamber doors closed on them once again, yet 51 would live to see another day.

Their number included one boy, who had hidden beneath clothing before stealing into the ranks of those who had been saved. Yaakov tried, and failed, to block out the despair of the doomed. ‘Their screams reached the heavens,’ he recalled. ‘They knew this was it.’

The 51 would not know why they had been spared, and what they were needed for, until they returned to barracks. Their only clue came from a member of the Sonderkommando, who murmured: ‘You are saved because Dr Mengele needs you to work.’

A second Sonderkommando member was incredulous: ‘No one has left here alive. You are the first. This has never happened.’ The truth emerged a little later, when Mengele entered the block.

Hershel Herskovic, here showing his number tattoo, was among those who escaped the gas chambers, after being told that Josef Mengele needed them for work

Miracle by Michael Calvin & Naftali Schiff (Bantam, £22), is published this week

He told the boys a train, loaded with potatoes, had arrived at the railway. It would be the youngsters’ job to help send some to frontline German troops.

Mordechai Eldar believed the Germans were just trying to save their own skins. The 51 were merely an insurance policy.

In an interview two years ago, he said that because the war was nearing its end, the Nazis realised they would have to answer for the gassing programme. Also, they were running out of people to work. By now, many of those in Birkenau were half-dead.

Once the potatoes were loaded on a convoy of trucks, the boys were told to dig trenches in driving rain to plant the remaining potatoes.

Mordechai Eldar later remembered: ‘The SS soldiers guarded us and forbade us to eat the potatoes. Whoever did so and was caught was severely beaten.’

He reasoned that the aim was to produce a crop of potatoes before Russian troops arrived, but as he calculated, it was futile. The camp was starting to be wound down.

The boys no longer noticed the flames from the chimneys, nor the smell from the ovens.

With Germany losing the war, Crematorium 4 was dismantled by the end of 1944 after plans were made to blow up three other crematoria. The SS duly began the process of covering their tracks by destroying prisoner records, burning all ledgers containing arrival details. Pits containing human ashes were bulldozed.

However, though saved from the gas chambers, a new ordeal awaited the boys: they were forced to evacuate and herded on to the road to march or die.

When Auschwitz was evacuated between January 17 and 21, 1945, most of the remaining 200 or so Hungarian boys were ordered to walk westwards. They had no food or water. The SS shot anyone who stumbled, hesitated or dared to break ranks. Some, frozen and hungry, died.

Dugo Leitner, another of the 51, who passed away in July 2023, vividly recalled sustaining himself by eating slugs: ‘How we chewed those big, bubbly ones.’

Another 35-mile march into Austria, on which around a quarter of the 20,000 prisoners died, was the precursor to eventual freedom when many were finally coaxed back to health in a military hospital.

Hershel Herskovic remembers the pity in the eyes of their American liberators in early May 1945 when they came across one survivor: ‘He could no longer walk, and his eyes were bulging. They saw us and shook their heads. They obviously didn’t think there was any way we could live.’

Among those boys who survived the gas chamber and march of death, one went on to become a teacher in New York, another a rabbi in Manchester, another the owner of a paper-products firm in Canada and another a lieutenant-general in the Israel Defence Forces. Avigdor Neumann, an eye witness to the 51’s reprieve, regularly revisited Auschwitz to share his experiences.

He said: ‘We went through all Hell. But you can turn away from all those troubles, and start off a new life, because God will help you. My message is that your strength is nothing, your wisdom is nothing, your wealth is nothing. The main thing is to hold on, to have belief, to be a good person.’

Wolf Greenwald, another of the 51, harboured one regret. He felt cheated that Dr Mengele managed to evade justice. The Nazi monster drowned in 1979 after suffering a stroke while swimming in Brazil.

Hershel Herskovic had been blinded by a combination of typhus and the brutality of an SS guard, who hit him repeatedly in the head with a rifle butt. But he moved to London and built a property business. A photo of him went viral during the Covid epidemic when, at the age of 93, he got a Covid jab in the arm bearing his Auschwitz tattoo.

Eighty years on from that horrific ordeal, supported by a grey cushion in a bay window on the top floor of his London home, he said: ‘Never give up, whatever the circumstances. Do your best to prevail. Doing something positive, or thinking positively, creates an environment of hope and expectation. If you give up, you are easily lost.’

• Adapted from Miracle by Michael Calvin & Naftali Schiff (Bantam, £22), published this week. © Michael Calvin and Naftali Schiff 2026. To order a copy for £19.80 (offer valid to 07/02/26; UK P&P free on orders over £25) go to mailshop.co.uk/books or call 020 3176 2937.