The demented Roman Emperor Caligula once mused that if all the people of Rome had one neck he would cut it just to be rid of his troublesome people.

The trouble was there were simply too many Romans to kill them all.

Many centuries later, the brutal Soviet dictator Josef Stalin reflected that he would have liked to deport the entire Ukrainian nation, but 20 million were too many to move even for him.

So he found another solution: starvation.

Now, 75 years after one of the great forgotten crimes of modern times, Stalin's man-made famine of 1932/3, the former Soviet republic of Ukraine is asking the world to classify it as a genocide.

The Ukrainians call it the Holodomor - the Hunger.

Millions starved as Soviet troops and secret policemen raided their villages, stole the harvest and all the food in villagers' homes.

They dropped dead in the streets, lay dying and rotting in their houses, and some women became so desperate for food that they ate their own children.

If they managed to fend off starvation, they were deported and shot in their hundreds of thousands.

So terrible was the famine that Igor Yukhnovsky, director of the Institute of National Memory, the Ukrainian institution researching the Holodomor, believes as many as nine million may have died.

For decades the disaster remained a state secret, denied by Stalin and his Soviet government and concealed from the outside world with the help of the 'useful idiots' - as Lenin called Soviet sympathisers in the West.

Russia is furious that Ukraine has raised the issue of the famine: the swaggering 21st-century state of Prime Minister Putin and President Medvedev see this as nationalist chicanery designed to promote Ukraine, which may soon join Nato and the EU.

They see it as an anti-Russian manoeuvre more to do with modern politics than history. And they refuse to recognise this old crime as a genocide.

They argue that because the famine not only killed Ukrainians but huge numbers of Russians, Cossacks, Kazakhs and many others as well, it can't be termed genocide - defined as the deliberate killing of large numbers of a particular ethnic group.

It may be a strange defence, but it is historically correct.

So what is the truth about the Holodomor? And why is Ukraine provoking Russia's wrath by demanding public recognition now?

The Ukraine was the bread basket of Russia, but the Great Famine of 1932/3 was not just aimed at the Ukrainians as a nation - it was a deliberate policy aimed at the entire Soviet peasant population - Russian, Ukrainian and Kazakh - especially better-off, small-time farmers.

It was a class war designed to 'break the back of the peasantry', a war of the cities against the countryside and, unlike the Holocaust, it was not designed to eradicate an ethnic people, but to shatter their independent spirit.

So while it may not be a formal case of genocide, it does, indeed, rank as one of the most terrible crimes of the 20th century.

To understand the origins of the famine, we have to go back to the October 1917 Revolution when the Bolsheviks, led by a ruthless clique of Marxist revolutionaries including Lenin, Trotsky and Stalin, seized power in the name of the workers and peasants of the Russian Empire to create a Marxist paradise, using terror, murder and repression.

The Russian Empire was made of many peoples, including the Russians, Ukrainians, Kazakhs and Georgians, but the great majority of them, especially in the vast arable lands of Ukraine, southern Russia, the northern Caucasus, and Siberia, were peasants, who dreamed only of owning their own land and farming it.

Initially, they were thrilled with the Revolution, which meant the breakup of the large landed estates into small parcels which they could farm.

But the peasants had no interest in the Marxist utopian ideologies that obsessed Lenin and Stalin.

Once they had seized their plots of land, they were no longer interested in esoteric absurdities such as Marx's stages in the creation of a classless society.

The fact is they were essentially conservative and wanted to pass what little wealth they had to their children.

This infuriated Lenin and the Bolsheviks, who believed that the peasantry, especially the ones who owned some land and a few cows, were a huge threat to a collectivist Soviet Russia.

Lenin's hatred of the peasantry became clear when a famine occurred in Ukraine and southern Russia in 1921, the inevitable result of the chaos and upheaval of the Revolution.

With his bloodthirsty loathing for all enemies of the Revolution, he said 'Let the peasants starve', and wrote ranting notes ordering the better-off peasants to be hanged in their thousands and their bodies displayed by the roadsides.

Yet this was an emotional outburst and, ever the ruthless pragmatist, he realised the country was so poor and weak in the immediate aftermath of its revolutionary civil war that the peasants were vital to its survival.

So instead, he embraced what he called a New Economic Policy, in effect a temporary retreat from Marxism, that allowed the peasants to grow crops and sell them for profit.

It was always planned by Lenin and his fellow radicals that this New Economic Policy should be a stopgap measure which would soon be abandoned in the Marxist cause.

But before this could happen, Lenin died in 1924 and Stalin defeated all his rivals for the Soviet leadership.

Then, three years later, grain supplies dropped radically. It had been a poor crop, made worse by the fact that many peasant farmers had shifted from grain into more lucrative cotton production.

Stalin travelled across Russia to inspect supplies and ordered forcible seizures of grain from the peasantry.

Thousands of young urban Communists were drafted into the countryside to help seize grain as Stalin determined that the old policies had failed.

Backed by the young, tough Communists of his party, he devised what he called the Great Turn: he would seize the land, force the peasants into collective farms and sell the excess grain abroad to force through a Five Year Plan of furious industrialisation to make Soviet Russia a military super power.

He expected the peasants to resist and decreed anyone who did so was a kulak - a better-off peasant who could afford to withhold grain - and who was now to be treated as a class enemy.

By 1930, it was clear the collectivisation campaign was in difficulties.

There was less grain than before it had been introduced, the peasants were still resisting and the Soviet Union seemed to be tottering.

Stalin, along with his henchman Vyacheslav Molotov and others, wrote a ruthless memorandum ordering the 'destruction of the kulaks as a class'.

They divided huge numbers of peasants into three categories.

The first was to be eliminated immediately; the second to be imprisoned in camps; the third, consisting of 150,000 households - almost a million innocent people - was to be deported to wildernesses in Siberia or Asia.

Stalin himself did not really understand how to identify a kulak or how to improve grain production, but this was beside the point.

What mattered was that sufficient numbers of peasants would be killed or deported for all resistance to his collectivisation programme to be smashed.

In letters written by many Soviet leaders, including Stalin and Molotov, which I have read in the archives, they repeatedly used the expression: 'We must break the back of the peasantry.' And they meant it.

In 1930/1, millions of peasants were deported, mainly to Siberia. But 800,000 people rebelled in small uprisings, often murdering local commissars who tried to take their grain.

So Stalin's top henchmen led armed expeditions of secret policemen to crush 'the wreckers', shooting thousands.

The peasants replied by destroying their crops and slaughtering 26 million cattle and 15 million horses to stop the Bolsheviks (and the cities they came from) getting their food.

Their mistake was to think they were dealing with ordinary politicians.

But the Bolsheviks were far more sinister than that: if many millions of peasants wished to fight to the death, then the Bolsheviks were not afraid of killing them.

It was war - and the struggle was most vicious not only in the Ukraine but in the north Caucasus, the Volga, southern Russia and central Asia.

The strain of the slaughter affected even the bull-nerved Stalin, who sensed opposition to these brutal policies by the more moderate Bolsheviks, including his wife Nadya.

He knew Soviet power was suddenly precarious, yet Stalin kept selling the grain abroad while a shortage turned into a famine.

More than a million peasants were deported to Siberia: hundreds of thousands were arrested or shot.

Like a village shopkeeper doing his accounts, Stalin totted up the numbers of executed peasants and the tonnes of grains he had collected.

By December 1931, famine was sweeping the Ukraine and north Caucasus.

'The peasants ate dogs, horses, rotten potatoes, the bark of trees, anything they could find,' wrote one witness Fedor Bleov.

By summer 1932, Fred Beal, an American radical and rare outside witness, visited a village near Kharkov in Ukraine, where he found all the inhabitants dead in their houses or on the streets, except one insane woman. Rats feasted on the bodies.

Beal found messages next to the bodies such as: 'My son, I couldn't wait. God be with you.'

One young communist, Lev Kopolev, wrote at the time of 'women and children with distended bellies turning blue, with vacant lifeless eyes.

'And corpses. Corpses in ragged sheepskin coats and cheap felt boots; corpses in peasant huts in the melting snow of Vologda [in Russia] and Kharkov [in Ukraine].'

Cannibalism was rife and some women offered sexual favours in return for food.

There are horrific eye-witness accounts of mothers eating their own children.

In the Ukrainian city of Poltava, Andriy Melezhyk recalled that neighbours found a pot containing a boiled liver, heart and lungs in the home of one mother who had died.

Under a barrel in the cellar they discovered a small hole in which a child's head, feet and hands were buried. It was the remains of the woman's little daughter, Vaska.

A boy named Miron Dolot described the countryside as 'like a battlefield after a war.

'Littering the fields were bodies of starving farmers who'd been combing the potato fields in the hope of finding a fragment of a potato.

'Some frozen corpses had been lying out there for months.'

On June 6, 1932, Stalin and Molotov ordered 'no deviation regarding amounts or deadlines of grain deliveries are to be permitted'.

A week later, even the Ukrainian Bolshevik leaders were begging for food, but Stalin turned on his own comrades, accusing them of being wreckers.

'The Ukraine has been given more than it should,' he stated.

When a comrade at a Politburo meeting told the truth about the horrors, Stalin, who knew what was happening perfectly well, retorted: 'Wouldn't it be better for you to leave your post and become a writer so you can concoct more fables!'

In the same week, a train pulled into Kiev from the Ukrainian villages 'loaded with corpses of people who had starved to death', according to one report.

Such tragic sights had no effect on the Soviet leadership.

When the American Beal complained to the Bolshevik Ukrainian boss, Petrovsky, he replied: 'We know millions are dying. That is unfortunate, but the glorious future of the Soviet Union will justify it.'

Stalin was not alone in his crazed determination to push through his plan.

The archives reveal one young communist admitting: 'I saw people dying from hunger, but I firmly believed the ends justified the means.'

Though Stalin was admittedly in a frenzy of nervous tension, it was at this point in 1932 when under another leader the Soviet Union might have simply fallen apart and history would have been different.

Embattled on all sides, criticised by his own comrades, faced with chaos and civil war and mass starvation in the countryside, he pushed on ruthlessly - even when, in 1932, his wife Nadya committed suicide, in part as a protest against the famine.

'It seems in some regions of Ukraine, Soviet power has ceased to exist,' he wrote.

'Check the problem and take measures.' That meant the destruction of any resistance.

Stalin created a draconian law that any hungry peasant who stole even a husk of grain was to be shot - the notorious Misappropriation of Socialist Property law.

'If we don't make an effort, we might lose Ukraine,' Stalin said, almost in panic.

He dispatched ferocious punitive expeditions led by his henchmen, who engaged in mass murders and executions.

Not just Ukraine was targeted - Molotov, for example, headed to the Urals, the Lower Volga and Siberia.

Lazar Kaganovich, a close associate of Stalin, crushed the Kuban and Siberia regions where famine was also rife.

Train tickets were restricted and internal passports were introduced so that it became impossible for peasants to flee the famine areas.

Stalin called the peasants 'saboteurs' and declared it 'a fight to the death! These people deliberately tried to sabotage the Soviet stage'.

Between four and five million died in Ukraine, a million died in Kazakhstan and another million in the north Caucasus and the Volga.

By 1933, 5.7 million households - somewhere between ten million and 15 million people - had vanished. They had been deported, shot or died of starvation.

As for Stalin, he emerged more ruthless, more paranoid, more isolated than before.

Stalin later told Winston Churchill that this was the most difficult time of his entire life, harder even than Hitler's invasion.

'It was a terrible struggle' in which he had 'to destroy ten million. It was fearful. Four years it lasted - but it was absolutely necessary'.

Only in the mind of a brutal dictator could the mass murder of his own people be considered 'necessary'.

Whether it was genocide or not, perhaps now the true nature of one of the worst crimes in history will finally be acknowledged.

• Sashenka, a novel of love, family, death and betrayal in 20th century Russia, by Simon Sebag Montefiore, is out now.

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