Released on the 85th anniversary of the Turkish Republic founded by Atatürk, Mustafa is playing to capacity audiences, including busloads of schoolchildren. It was seen by nearly half a million people in its first five days.

However, the supposedly humanizing portrait of the man who abolished the Islamic Caliphate and set Turkey on the road to modernization has upset many in the secularist establishment. "Atatürk is shown as lonely and without hope, with a weakness for women, who drinks a bottle of rakı a day and regrets things he has done. This is simply not true," complained Deniz Baykal, the leader of the opposition Republican People's Party (CHP), which Atatürk founded.

The film begins with the secretive efforts of a lonely young boy who has just lost his father to join a military school against his mother's wishes.

Ambitious and critical, he is shown as a rebellious student before becoming an officer in the Ottoman army. Determined from an early age to transform the impoverished Ottoman Empire into a secular republican society, he leads his followers to victory in the 1919-23 independence war.

However, the suicide of his lover and his failed marriage left Atatürk without family, and some of his closest friends were found guilty of an attempt to assassinate him. When he later tours the country he is depressed to realise that even his modern Turkey remains mired in poverty and misery.

Towards the end of his life, when he hands over the reins of power, he is shown as wandering his residences in Ankara and İstanbul in boredom and frustration, drinking and smoking heavily, sometimes drifting off and sometimes crying with emotion at what he describes in his diaries as tedious dinners with the same old crowd.

Worried about his legacy, he invites the sculptor of the Fascist leader Benito Mussolini to create imposing, heroic statues of himself. He is shown making mistakes and having regrets, as a military and political strongman (a dictator, according to the international press at the time) who espouses radical views.

All this goes against official depictions of a strong, silent, all-seeing sage who was loved by one and all and could do no wrong.

The current constitution, written after a military coup in 1980, refers to Atatürk as immortal. Ironically, attempts to make reforms as radical as the ones he saw through are today blocked in his name. There is even a law against insulting Atatürk, which led to his ex-wife's biographer being taken to court.

The film's major sponsor, Turkcell, the mobile phone group, suspected that all was not well with Mustafa and withdrew its support at the last minute, amid worries that it would lose customers. The ensuing furor took the mild-mannered film-maker Can Dündar by surprise: his usual romantic historical documentaries rarely court anything approaching controversy. "If the film has done any harm it is to those who for years have used his name to hide his revolutionary character, allow his works to be censored, imprison him in cliches by dogmatising him despite his own objections and who profit from his name," Mr Dündar said in his defence. "Atatürk had nothing to hide."

A more level-headed assessment of Atatürk has been slowly gaining currency in his homeland, but Turkish institutions still keep important personal documents under lock and key and schools teach his story with dogmatic zeal.

"I really liked the film and I liked the Atatürk in it," said Ege, 14. "At school he is shown as this distant hero but here he is, a man with flaws; he seemed much nicer. Anyway, why should someone's personal life diminish any of his achievements?"