The decision to screen a graphic documentary, 9/11, marking the first anniversary of the suicide hijackings on the US, has been defended by the BBC.

Although the film got a mixed reception when it was screened on the US CBS network in March, it drew an average audience of nearly 39 million viewers - one third of all people watching TV at that time.

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It was shown amid strong protests from many of the victims' families, who complained that its graphic footage brought back horrific memories.

The BBC will broadcast the film as part of a special day of programming on 11 September, to remember the attacks on the US last year.

The film was being made as the hijackers struck

Before its US screening, charities involved with helping survivors and victims' families pleaded with CBS not to show footage of the two hijacked planes which crashed into the World Trade Center in New York, killing nearly 3,000 people.

But a spokesman for the BBC said the documentary was not intended to cause offence.

"It is just a reportage. To suggest it is shocking or controversial is far from the truth," he said.

"I think moving would probably be a better word to use rather than shocking. Obviously we would not show something that would cause a great amount of offence to people."

The film-makers were shooting footage of firefighters at the time

On 11 September 2001 the 110-storey World Trade Center was struck by two planes as horrified New Yorkers looked on.

A third plane struck the Pentagon in Washington, causing the evacuation of the military and intelligence building as it burned.

Another passenger jet crashed in Pennsylvania, south-east of Pittsburgh, killing everyone on board - its intended target was believed to be the Maryland presidential retreat, Camp David.

The programme includes film shot by French journalists Jules and Gideon Naudet, who were in New York making a film about firefighters when the World Trade Center attacks took place.

They kept their cameras running and also recorded scenes inside the buildings of workers trying to escape.

'Trauma'

Many of those who died in New York came from nearby Bergen County, and area prosecutor William Schmidt had urged CBS to delay its screening of the documentary.

"We are particularly concerned about the potentially negative psychological effects that graphic details of death and destruction may have on the thousands of individuals who have been traumatised by the events of 11 September," he said.

Carie Lemack, 26, president of Families of September 11, also expressed deep concern.

"They're going to show my mom exploding," she said. Her mother, Judy Larocque, died on American Airlines Flight 11.

'Resilience'

"We are a country in which we don't show public executions, and that's basically what this boils down to," she told the New York Times.

But she conceded some members of her lobbying group wanted to see the documentary.

"One, some people want to see what happened inside the building," she said.

"Or two, they don't want people to forget."

The New York Times called it "an important firsthand piece of history" while the New York Daily News called it "a tale of love, duty and resilience".

It has also been nominated for six Emmy awards, along with another documentary shown by the rival HBO network in May, In Memoriam: New York City, 9/11/01.

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