The BBC has said its documentary about Moors murderer Myra Hindley is "important", despite outrage from the victims' families.

The film has been branded "a disgrace and an insult" by the families, and father of one murdered girl is boycotting an advance screening.

Alan West, whose daughter Leslie Ann was murdered by Hindley, said: "Why can't the families be spared the constant indignity of Hindley's continuous publicity seeking?"

The families also feel they have been given less media coverage than Hindley and her accomplice Ian Brady over the years.

But BBC Director of Television Alan Yentob said the film complemented the national debate over the length of life sentences. He said it is the third time in three decades the BBC has "tackled the subject".

"The terrible crimes of Myra Hindley and Ian Brady have had such a profound effect that we are still struggling to understand how such acts could have been committed," he said.

"This is an important film which we hope will contribute to and help inform the debate over whether life really should mean life."

"Hindley and Brady, the "Moors murderers", killed five children and buried their bodies on Saddleworth Moor, near Manchester.

In 1966, Hindley and Brady were convicted of murdering two children, 10-year-old Lesley Ann Downey and 17-year-old Edward Evans. Brady was also convicted of murdering 12-year-old John Kilbride.

They later confessed to two other murders - those of 16-year-old Pauline Reade and Keith Bennett, 12.

The BBC film, Modern Times: Myra Hindley, asks "whether some crimes are so terrible that the people who commit them should die behind bars".

It features 150 letters she has written to the producer, read by an actress, telling the story of her meeting with Brady and their relationship.

Hindley's voice is also heard on the producer's answering machine, and Detective Chief Superintendent Geoff Knupfer, who was involved with the investigation, explores the validity of her call to be released.

Archive footage explores the devastating impact the murders have had on the families.

Victims' families' spokesman Norman Brennan said: "Why is it that we credit any time to a murderess? Why do we give her any credit when she has committed homicide?"

Modern Times' executive producer Alex Holmes defended the programme, saying: "This film is not a platform for Hindley but an attempt to reach some understanding of the terrible crimes that happened."

Mr Holmes said: "It's investigating whether life should mean life, an important and current debate that is going on.

Hindley, who lost an appeal against a ruling that she must spend her life in jail, has been dubbed "the most evil woman in Britain" by the press. But her supporters say she is a reformed woman.

Modern Times can be seen on BBC Two on 1 March at 2100 GMT.