BERLIN (Reuters) - Erwin Rommel, the World War Two German field marshal celebrated as the brilliant and humane "Desert Fox", is portrayed in a new film as a weak man torn by his loyalty to Adolf Hitler and the dawning realization that he was serving a devil.

The drama, due to be broadcast on the public ARD television on Thursday, has angered Rommel's son and granddaughter who believe it underplays his role in the resistance against Hitler.

Rommel was forced to commit suicide in 1944 after Hitler suspected the general of being linked to the July 1944 plot to kill him, though historians disagree about how close he was to the failed assassination attempt.

Nazi propaganda feted Rommel as a military genius after his successful, bold offensives against the Allies in North Africa from 1941 until late 1942 when his Afrikakorps was defeated at El Alamein, a battle commemorated in London last week by the dwindling band of surviving British and Commonwealth veterans.

Even wartime British Prime Minister Winston Churchill hailed Rommel as a "great general".

Rommel's standing among his enemies was enhanced by his humane treatment of prisoners. The Afrikakorps eschewed the atrocities committed by the German army in other theatres of war, especially on the Eastern Front.

By 1944, in Normandy trying to defend the coast from an impending Allied landing, Rommel realized the war was lost and grew disillusioned. Despite having links to some of the plotters, he never joined the abortive July 20, 1944 conspiracy to assassinate Hitler.

"The idea is to demystify Rommel," producer Nico Hofmann told Reuters.

"There is a lot of speculation surrounding the myth of Rommel. To some he is a brave, proud soldier, the 'Desert Fox'. Some people don't know he committed suicide under pressure from Hitler and think he perished in the war and there are many questions about how close he was to the resistance."

"These are taboos, subjects for discussion and historical evaluation," he said.

Film director Niki Stein described Rommel as a "weak man" who chose to look away and many historians say he was primarily bent on serving Hitler to advance his career.

Rommel's family has denounced the script of the 6 million euro film which focuses on his growing internal conflict during the seven months of his life leading up to his death.

His son, Manfred - who was 15 when his father died and is now 83 - and granddaughter wrote to the producers last year accusing the script of the film "Rommel" of presenting "lies".

They argued that he played a greater role in the resistance than the producers believed, said Hofmann.

The family have declined to talk to media about the film.

CYANIDE ULTIMATUM

Historians say the film is important as it will show millions of viewers the dramatic last months of the general's life and the dilemma faced by many Germans who felt a sense of duty to their country, but were disenchanted with Hitler.

"Please watch, this film explains a little how it was back then with our grandparents, with Hitler, with fear, with joining in," wrote a columnist in top-selling Bild daily, which has been serializing Rommel's life.

"The Rommel film shows how a man believes he is serving a king and realizes too late that he is a devil."

Other newspapers have also run long articles on the Rommel figure and the authoritative weekly Der Spiegel splashed "The Myth of Erwin Rommel" on its cover this week.

The film shows how a conflicted general, who was one of the Nazi regime's biggest propaganda tools, gradually turned against Hitler. In line with the historical evidence, it leaves open his role in the plot against Hitler led by Claus von Stauffenberg.

Although he had contact with some of those involved, his son has written that he knew nothing of the assassination attempt.

Rommel was wounded by a Spitfire attack on his staff car days before the July 20 coup attempt, but soon after the plot ringleaders were executed Hitler grew suspicious about him.

Realizing the potential damage of putting Rommel on trial for treason, Hitler sent two officers to put an ultimatum to his once favorite general: if he wanted his wife and son to be looked after, he should swallow a cyanide capsule.

Hitler wrote to his widow and gave the field marshal a state funeral with his coffin draped in a swastika flag.

"I don't see him as a hero. He is a tragic figure. He was a weak man drawn into an incredible internal conflict," Stein, the director and author of the screenplay, told Reuters.

"I hope young Germans watch. We're talking about our grandparents. It explains a lot about the way people act in a dictatorship."

With popular actor Ulrich Tukur playing the main role, Stein thinks people will identify with Rommel but not necessarily sympathize with him. "Perhaps they will be shocked when they realize he is not so clean," he said.

Underscoring the many contradictions of his character, Rommel's legacy has shifted over the years.

Immediately after World War Two, Germans latched on to the myth of Rommel as a "soldier's soldier" who had no close links to Nazi ideology and was forced to kill himself by the regime.

Much was made of the behavior of his Afrikakorps and his decision to disobey Hitler's "victory or death" order at El Alamein and instead oversee a retreat which saved many lives.

"By the 1970s a German destroyer and army barracks were named after him," said history Professor Soenke Neitzel, who has written about Rommel and advised the filmmakers.

He was favorably portrayed in 1951 by James Mason in "The Desert Fox", which gave prominence to his disputed role in the von Stauffenberg plot.

But many historians say it is implausible that a field marshal who regularly met top Nazis, including Hitler, did not know of the Holocaust, a point critics say the film brushes over.

"On the one hand he didn't commit war crimes that we know of and ordered a retreat at El Alamein despite Hitler's order," said Neitzel.

"But he took huge German casualties elsewhere and he was a servant of the regime. He was not exactly a shining liberal or Social Democrat. Mostly, he was interested in his career."