When Hitler turned on France the following spring Stalin stood aside, continuing to supply his ally with grain, metals, rubber and other vital commodities. Though it is clear from what we now know of Stalin’s conversations with his Politburo that he expected to be forced into war with Germany sooner or later, the timing of the Nazi attack — code-named Barbarossa or ‘Redbeard’ after a crusading Holy Roman Emperor — came as a devastating shock. The new, poorly defended border through Poland was overrun almost immediately, and within weeks the panic-stricken Red Army found itself defending the major cities of Russia herself.

Chief victim of this unpreparedness was Leningrad. Immediately pre-war, the city had a population of just over three million. In the twelve weeks to mid-September 1941, when the German and Finnish armies cut it off from the rest of the Soviet Union, about half a million Leningraders were drafted or evacuated, leaving just over 2.5 million civilians, at least 400,000 of them children, trapped within the city. Hunger set in almost immediately, and in October police began to report the appearance of emaciated corpses on the streets. Deaths quadrupled in December, peaking in January and February at 100,000 per month. By the end of what was even by Russian standards a savage winter — on some days temperatures dropped to -30 °C or below — cold and hunger had taken somewhere around half a million lives. It is on these months of mass death — what Russian historians call the ‘heroic period’ of the siege — that this book concentrates. The following two siege winters were less deadly, thanks to there being fewer mouths left to feed, and to food deliveries across Lake Ladoga, the inland sea to Leningrad’s east whose south-eastern shores the Red Army continued to hold. In January 1943 fighting also cleared a fragile land corridor out of the city, through which the Soviets were able to build a railway line. Mortality nonetheless remained high, taking the total death toll to somewhere between 700,000 and 800,000 — one in every three or four of the immediate pre-siege population — by January 1944, when the Wehrmacht finally began its long retreat to Berlin.