Irving Milchberg, who has died aged 86, was the wartime leader of the “cigarette sellers of Three Crosses Square,” a gaggle of Jewish youths who sold smokes to German officers in wartime Warsaw while covertly spiriting food into the city’s ghetto and smuggling arms to the resistance.

For four years Milchberg’s survival, along with approximately 20 other youngsters, relied on a balancing act of “extreme fear and extreme hubris.” By hiding in plain sight they went unnoticed even to the hawkish SS garrisoned at the heart of their trading patch. In occupied territory a Jewish surname could be a death sentence, so Milchberg adopted the gentile name “Henrik Rozowski” and later the nickname “Bull.” His friends were safely known by the Polish versions of Toothy, Hoppy, Conky, Baldy, Whitey, Carrot Top and Chopper. Like the Baker Street Irregulars, this gang of street urchins “bargained, haggled and undersold each other eagerly” while helping others in need.

After the establishment of the Warsaw Ghetto in November 1940 the Jewish community, approximately 30 per cent of the city’s population, had been jemmied into a district representing less than three per cent of the city’s space. Three Crosses Square sat in the Aryan area in the Central District, where a triumvirate of crosses capped St Alexander’s Church and two facing columns. It had been a major thoroughfare from the 18th century and during the occupation became a hub for the Nazi machine. The SS, German gendarmerie, and Gestapo were all stationed in its vicinity.

Yet Three Crosses Square was something of a haven from the horrors of war and the nearby ghetto. According to Joseph Ziemian, in his memoir The Cigarette Sellers of Three Crosses Square (1970), life there was “relatively normal”; and Milchberg and the crew bartered packets of cigarettes and theatre tickets. Even so, it was a dangerous business. Milchberg was careful and resourceful, acquiring a work permit for the Ostbahn railway yard, where he unloaded coal trucks.

The Ostbahn workers became a channel to resistance units within the ghetto. Using a network of contacts, including an uncle and a tram-conductor, Milchberg smuggled in small arms hidden in hollowed-out loaves (the only food allowed through the barricades). The weapons added to the cache used by the Jewish fighters in the Warsaw Uprising of April and May 1943.

To the other boys and girls he was a natural chief. “In their eyes he was grown-up and experienced,” wrote Ziemian. “Bull had authority.” Milchberg, however, took a practical view of his wartime bravery. “To tell you the truth, I never thought much,” he said last year. “If I had to do something, I did it. I didn’t have time to analyze it.”

Ignac Milchberg (later known as Irving) was born in Warsaw on September 15 1927 into a merchant family which traded in household goods. His upbringing was a happy and relatively affluent one. “Warsaw was once the centre of my universe,” recalled Milchberg late in life.

After the invasion his family was rounded up and placed in the segregated quarter, crammed into a single room above a grocery. His father “appraised the situation correctly early on and was among the first of the 'outside’ workers” – those allowed beyond the walls to work in the lumberyards. This kept the family in food. “The very idea of going to a favorite football field only five blocks away was like going to the moon,” Irving later recalled.

Milchberg lost his entire immediate family in the war. His father was executed in 1942 by a German gendarme after attempting to smuggle a packet of saccharine into the Ghetto. The sentry told him to run and then shot him in the back. “At this tragic moment, although only 15 years old, Bull showed a surprising energy and ability to cope. He established contact with other outside workers and through them exchanged clothes and other articles for food,” noted Ziemian.

In the wake of his father’s murder Milchberg was detained, but he managed to escape in the swirling crowds in the Umschlagplatz, which had become a holding pen for the Treblinka trains. On returning to the family’s room he found the door wide open – a bad sign. Inside, however, nothing had been touched. He cried out for his family, but there was no response. His mother and three sisters had been sent to Treblinka where they all perished. From 1940 to 1943, more than 400,000 of Warsaw’s Jews died in the walled Ghetto or in the camps.

Milchberg escaped two further deportation attempts, finding safety in the kindness of strangers: he was taken on as an apprentice to a cobbler then as assistant to an ice cream maker. The threat of death hung over all parties. While being chased in the street by anti-Semitic Poles he fell and seriously injured his leg. The cobbler, once again, hid him (this time in his attic) against the objections of his terrified wife, before delivering him to a sympathetic doctor.

Milchberg with his friend Conky during the war

After the war Milchberg relocated to Canada, where he settled in Niagara Falls and opened a jewelry store. It was there, in 1953, that he met his wife, Renee, a visiting tourist. Renee’s war had been similarly dramatic, as she had managed to survive for years in a Russian labor camp.

In 1993 Milchberg travelled to Warsaw, in the company of his daughter Anne, for the first time since emigrating. He was accompanied by a Canadian film crew. In Return To The Warsaw Ghetto, an hour-long documentary celebrating the 50th anniversary of the Uprising, he was left visibly shaken by the ghosts of his wartime youth. Hoppy (Josef Szindler) and Frenchy (Kazik Gelblum) were just two of the cigarette boys killed by the Germans. “You handle it by having a family, by creating a new life for yourself,” he declared in defiance. “We need to show those murderers that we survived, in spite of them.”

He is survived by his wife Renee, along with a son and a daughter.