As a reflection of the respective positions of the couple, it was all pretty accurate, though Elizabeth Longford, as the film chronicles, later came round to her husband's point of view about society's need to rehabilitate Hindley.
However, the script described uniformed servants bringing in dinner and clearing the dishes. As Frank Longford's friend, biographer (in 1994 when he was 89 and again in 2003 following his death in 2001), the director of the trust set up in his memory and the consultant on the film, it was one of the details I circled in red as wrong. He may have been a hereditary earl who inherited (and then gave away) a stately home in Ireland, but the Longfords were not wealthy and, as I can testify after many a dinner discussing politics, prisons or even how to bring up my children, they picked up their own dirty plates.
At our next script meeting, the writer Peter Morgan duly noted this tiny flaw, but when a fresh draft appeared, the family retainers were still there. Peter explained that HBO, the American co-producers, wanted them left in. For the film to appeal to a US audience, an English lord had to behave as Americans imagined an English lord would. Morgan, though, is a stickler for accuracy. It is, for him, one of the hallmarks of a genre he above all has effectively created in recent years. In recent months his play Frost/Nixon has sold out at London's Donmar Warehouse and The Queen, for which he wrote the script, has to date taken more than £4m at the UK box office. The docudrama inhabits a territory halfway between fact and fiction, actors and a script fleshing out real-life episodes in as authentic a way as possible. And so, no doubt to the consternation of American viewers hoping for another Brideshead, the servants don't make the final cut.
But the discussion about whether or not to include them was revealing. For Longford floats somewhere between drama and biography. As a dramatist Morgan was coming from one shore of that ocean, and as a biographer I was coming from the other. Our meeting in the middle was happy (though he doesn't like the term docudrama) but the accuracy question continued to dog us. I never quite worked out when it mattered and when it didn't.
So in Longford, Jim Broadbent, who plays the principal role, has his character's odd, lisping voice off to a T. He wears the food-stained green Irish Rugby Football Union ties that Frank wore. And thousands have been spent on prosthetics to make him look just like Longford. His portrait is so extraordinary that, watching an early cut at home, I found myself crying. It felt as if a man I had come to love dearly had suddenly walked back into my sitting room. When I confessed to another friend of Longford, the broadcaster Jon Snow, he admitted he had also shed a tear.
The film interweaves archive footage of Longford - for example, taking part in TV discussion programmes with relatives of Hindley's victims - to accentuate the impression that you are, in fact, watching a documentary account of the behind-the-scenes story of one man's crusade. Whole speeches by Broadbent's Longford are lifted directly from transcripts of talks by the man himself.
But, then, along come details that are just wrong, such as showing Longford in 1967, when he was in Harold Wilson's cabinet as Leader of the House of Lords, picking up a newly released prisoner from jail in his official car. Frank wouldn't have confused his personal mission with his public office, and would have taken the bus or a taxi (he never learnt to drive). But it was, Peter assured me, a necessary sacrifice of biography to the cause of drama. But are such compromises worth it?
When I got a call from my agent in 2003 saying that Peter Morgan was interested in my newly reworked Longford biography, The Outcasts' Outcast, I couldn't quite take it seriously. There is a whole shadow world where authors meet producers and scriptwriters to discuss adapting their work for the big or small screen. Rare indeed are those that go the distance.
The chances of Longford making it seemed slim. Though he was a tabloid headline-grabber in his lifetime as a 'loony lord', not only for his support of Hindley but also for his infamous Seventies campaign against pornography, he had been quickly forgotten after his death. But I was missing the most important point: Morgan's recent record of high-profile successes.
Morgan was also passionate about Frank. For him, Longford is about re-examining the challenge Frank's work with prisoners, and notably with Hindley, posed for the rest of us. Do we demonise and lock miscreants away for ever, or acknowledge that we are all flawed, accept that everyone is capable of reform, rehabilitation and redemption? And because of the power of television - not to mention the popular appeal of Jim Broadbent - Longford will reach many more people in one 90-minute burst on Channel 4 than all the efforts of the Longford Trust to continue Frank's work on prison reform.
However much I cherish his memory and his legacy, though, Frank was not my father (though he did insist on being chief usher at my wedding). I can therefore only guess at how it feels, so soon after the deaths of your parents, to see them reincarnated on screen. So for the Longford children, the parts of the film portraying their home life will be of great interest. In particular, they will dwell on the treatment of their mother, played by Lindsay Duncan, who is portrayed in the drama as something of a cipher, the individual whose volte-face on Hindley (achieved by a route that is completely out of character for the real woman) gives viewers the cue that a rethink of their prejudices may be appropriate.
As for Myra Hindley, emotionally she was brassy and hard on the outside. You had to work hard to get beyond that defence. Samantha Morton's Myra rolls over and purrs as soon as Broadbent's Longford compliments her on her smile.
What will make this delicate balancing act between drama and biography in Longford harder to take for Frank's family is the fact that it is a dynasty with a strong track record in the latter. His daughter Antonia Fraser and her daughters, Flora and Rebecca, for example, have both followed in Elizabeth Longford's footsteps as biographers of great distinction.
To create a rounded portrait of Longford as a family man as well as a dedicated campaigner, the film intercuts between his public and private life. In one scene, Broadbent and Duncan attend the launch of a new novel by the Longfords' daughter, Rachel Billington. It is hijacked by journalists asking about Hindley.
It adds considerably to the drama, to the proposition that his crusade had a negative impact on his family, but nothing remotely like it took place. Yet Billington is a novelist and the title shown on the billboard behind the actress playing her is indeed of one of the books. Like her siblings, she has made no public comment on the film, but whatever her views she has no comeback about the use of her name and her reputation as a writer in this way. Just as Marcia Williams had no legal right of redress over the use of her life in BBC4's The Lavender List or David Blunkett and Kimberly Quinn over Channel 4's A Very Social Secretary
Channel 4 has not ignored the family's feelings, however. The producers endeavoured to consult them, and they have been offered a chance to see it in private before it is broadcast. A donation was made to the Longford Trust. Similar concern has also been shown to the families of Hindley's victims. But however sincerely undertaken, this production is working in territory that only allows it to go so far in meeting any objections.
Some of the bigger claims that the film makes will, in any case, always be in the realms of conjecture. A central tenet of Morgan's picture of Longford is that he took up the Hindley crusade to fill the gap in his life left when his political career ended in 1968. It is a reasonable theory, but his motivations were much more complex.
So am I pleased with the result? Something that celebrates Longford and the questions he asked of society about prisoners is a very good thing.
But perhaps the last word is best left to Frank Longford himself. I don't have a hotline to heaven, where surely he must now be, but it's not necessary. Though he would alwazys claim that he only stepped into the spotlight for the good of the causes he held dear, in reality he loved publicity. Any biopic, docudrama, or whatever you care to call it, made about him in his lifetime, however warts-and-all its approach, would have had his full co-operation.
· Longford is on Channel 4 at 9pm on Thursday 26 October. Peter Stanford's The Outcasts' Outcast, is published in paperback by Sutton at £9.99
