LONDON (Reuters) - A film inspired by the 2005 London suicide bombings that killed 52 people explores the mistrust they stoked between communities and how Islamist radicals threatened to drown out the voice of moderate Muslims.

"Shoot on Sight," starring Greta Scacchi, is set in the capital just after the July 7 bombings and follows the story of a Muslim police officer thrust into the limelight when a Muslim man is mistaken for a bomber and shot dead.

Tariq Ali, played by Indian actor Naseeruddin Shah, finds himself caught between police officers who are prejudiced against him because of his race and religion and a Muslim community that shuns him for betraying them.

"They don't trust him in the department because he is a Muslim and they don't trust him at the mosque because he is a police officer," director Jagmohan Mundhra told Reuters ahead of the film's release in Britain on August 22.

"I have always admired British society for being the most tolerant. It's not just lip service, they have actually done it.

"Then the actions of a few suddenly start causing this chasm. It becomes us versus them, and I think all these years of blending, suddenly, in one night, comes to naught."

Mundhra, an Indian Hindu, was in London at the time of the attacks on the underground train system and a bus, and noticed how people's attitude to him changed because he was assumed by many to be a Muslim from South Asia.

Later the same month, a Brazilian man mistakenly believed to be a suicide bomber was shot dead by police. Mundhra used the incident as a trigger for his thriller, but made the victim a Muslim man instead.

He denied that "Shoot on Sight," the first feature film to deal with the July 2005 events, was insensitive to victims.

"I feel that you can't be an ostrich in the sand, you cannot ignore what is happening in society."

REAL EVENTS, CHARACTERS

As well as following Ali, a moderate Muslim, "Shoot on Sight" portrays a radical London cleric who encourages followers to turn to violence to address injustices he says have been carried out against Muslims around the world.

Played by Om Puri, imam Junaid is a charismatic teacher whose ideas appeal on one level and yet border on incendiary.

"Any progressive, liberal Muslim would agree with a lot of the arguments which he makes," Mundhra said. "But what he's suggesting to do about it is absolutely unacceptable in a civilized society."

Mundhra said he read speeches made by radical Muslim clerics Abu Hamza al-Masri and Omar Bakri Mohammed during his research. Bakri has been banned from Britain and Hamza has been jailed.

The director said radical Muslims had succeeded in drowning out the voice of mainstream Muslims since the September 11, 2001 attacks in the United States and the 2005 bombings in London.

"The noise caused by the actions of a few radical extremist Muslims has silenced the voice of the majority," he argued.

"However, I also feel that the Muslim majority, which I believe my film is representing, should also speak up."

Italian-born Scacchi, star of films like "White Mischief" and "Presumed Innocent," plays Ali's English wife, and strains in society at large are reflected in the mixed-race marriage.

The actress said she took on the role in order to confront her own prejudices in the aftermath of the London attacks.

"My experience, I have to confess, was my own prejudice, my own fear," she told Reuters.

She said she would "notice if there was anyone getting on the same bus or tube (subway train) as me, or particularly an airplane, where your mind can't help leaping to those sort of possibilities."

But, she added, it had been far harder for Britain's large Muslim minority, which had "suffered enormously."

(Editing by Paul Casciato)