In 1991, four men sat down in Belfast to write a book of the dead.

They resolved to put on record the stories of what happened to every man, woman and child killed during Northern Ireland's Troubles.

Their testament to suffering would take eight years of painstaking research. They detailed 3,700 lives shattered. Their book was 'Lost Lives'.

Now, two film makers and a host of Irish actors have followed in those writers' footsteps.

Taking Lost Lives as their inspiration, they have created a requiem for the Troubles dead.

Liam Neeson, Ciarán Hinds, Kenneth Branagh, Adrian Dunbar and Bronagh Waugh are among a long list of acting talent from Northern Ireland who have given their voices to the film.

The book was written by veteran NI journalist David McKittrick, BBC journalists Chris Thornton and the late Seamus Kelters, and political commentator Brian Feeney. At a later stage, David McVea joined in.

First published in 1999, it was an act of remembrance, lest a single life be forgotten.

It is considered the go-to reference book and an authority on the Troubles.

In the Irish Times in 2006, journalist Susan McKay wrote: "A Tyrone man bought five copies. Five members of his family, all in the security forces, had been killed.

"A Donegal man found out from the book that it was the UVF, and not the IRA, that had killed his brother - as his family had supposed for 30 years.

"It has been read out in churches, Protestant and Catholic. A woman wept so much over the book in a shop she left mascara stains on the page at which she'd opened it."

'War is Hell'

The new film, which had its premiere in London on Thursday night, tells individual stories from the book, using archive footage, music and the book's words spoken by actors to bring them to life.

Dermot Lavery and Michael Hewitt of DoubleBand film say theirs is not a documentary, but rather a "creative response" to the book.

They found their inspiration between the pages of the stout volume where each victim's name and age are listed along with the date and the details of their death.

Their film melds strikingly beautiful images with the crackle of gunfire and the ugly thud of bombs.

"It is a reminder that war is Hell," said Lavery.

"For us, it is a cinematic event that addresses the past, but looks to the future."

Lost Lives - a production commissioned by BBC Northern Ireland with funding from NI Screen - is a film about humanity and inhumanity, about innocence and experience during the Troubles - a local story that played out for more than 30 years on a worldwide stage.

It marries the beauty of the natural world with old footage from past atrocities.

The camera holds the face of a toddler in a knitted bonnet sitting in her pram at a street corner, watching her world collapse.

A woman stares out from behind lace curtains as violence unfolds on her street.

A man is filmed abandoning his home, loading his worldly possessions on to a trailer with an air of resignation, lumping a huge statue of the Virgin Mary on the top.

The film is an elegy that flicks from children playing with toy guns to the crackle of real gunfire.

The viewer is brought back again and again to the fluttering pages of the Lost Lives book and to story after story of heartbreak.

We hear about the parents who left Belfast after their child was shot dead... but they had to come back.

"I wasn't content knowing that Patrick was buried here, I wanted to be near him," said Patrick Rooney's mother.

We hear the words of Mary Isobel Thompson's widower: "She was a happy wee woman, the world's best.

"There was just the two of us, we had no family, so we always went everywhere together. Now I am by myself. Sometimes I do not realise, I think I hear her calling for me..."

And there is Philip Rafferty, just 14, abducted, hooded and shot dead. He had been on his way to a music lesson.

His Jewish uncle wrote a letter to a newspaper. He said he had lost a cousin to Hitler's gas chambers and now, more than 30 years later, another child had died needlessly.

He said Philip was a small frail boy who suffered from asthma. He was his parents pride and joy. He was barely 14.

"That's all the years Philip Rafferty had... Why did he die?"

Michael Hewitt and Dermot Lavery ensured that every name in the book Lost Lives appears in the film We started making the film three years ago, but we were having conversations about it long before that.

Lost Lives is a reference book, but it represents much more than that. The challenge was how do you make a film from a book like that?

We made a commitment that every name in the book should be listed in the film.

Then we found extracts where there was a quote from a family member that reflected the hurt felt by those left behind. We were very much drawn to that.

The actors all came on board so readily. There was something of real value in the fact that they were lending their support and their voices to the film.

We felt enormously honoured. Nobody needed persuading or to be asked a second time.

We are very clear that we are living in troubled times. We need to remember the cost when things are settled through violence.

When you hold that book in your hand, you can feel the weight of all that was lost, all the lives.

You have to ask why.

Lost Lives, the film, is being released to mark 50 years since the Troubles began.

It received its world premiere at the BFI London Film Festival on Thursday, followed by a question-and-answer session with the film makers and narrators which will feature at UK screenings on 23 October.

Actors Stephen Rea, Brid Brennan, Roma Downey, Michelle Fairley, Brendan Gleeson, Dan Gordon, James Nesbitt, Conleth Hill, Susan Lynch, Emer O'Connor, Stephen Rea, Judith Roddy, Michael Smiley, Bronagh Waugh, Des McAleer, Martin McCann, Ian McElhinney and Sean McGinley also lend their voices.

The film is also being shown at Belfast's QFT cinema from Friday 11 October. It will be shown on BBC television later this year.