I first began work on this film ten years ago, which is an indication of how long films can take to reach audiences; if they ever do at all. Jonathan Cavendish, its producer, told me the story of his parents, and I knew at once I wanted to write it as a screenplay, even though at that point there was no finance available. I was happy to embark on the project with Jonathan, and let it lead wherever it might. The result is now completed, and has proved to be one of the best experiences of my life as a screenwriter. Not since 'Shadowlands' has a work of mine been translated to the screen intact. I'm lucky to have fallen into the hands of a director as wise, as skilled, and as remarkable with actors, as Andy Serkis; and I'm lucky to have been graced with two lead actors of the talent of Andrew Garfield and Claire Foy.

So I love the film, and find it moving every time I watch it. But of course I'm aware that there are many who don't much like it.

I've puzzled over this, wanting to discover what it is they react against, and I think I do understand it. There's a chirpy quality to the central relationship that I can see could come across as unreal; and somehow, despite the terrible disability at the heart of the story, they don't quite suffer enough; and the style of shooting, particularly at the start, gives a picture of posh fun which can grate. Beyond that - and I've been careful not to read the wording of the negative reviews - I have to give up, and admit that this is my emotional style, and I must own it, and accept the fact that to some it rings false.

This line of thought does lead me to wonder something of a more general nature. I'm constantly foxed by the excellent reviews given to films that seem to me to be false and shallow in their understanding of the human condition; films that, on the whole, present a dark view of life. Some examples might be the Coen Brothers 'No Country for Old men', or Tom Ford's 'Nocturnal Animals'. I can't see what's to praise in these exercises in cynicism, other than their visual style. This makes me wonder if what to me is a cause for dislike is precisely what is being liked. If so, why? It strikes me then that we look to films to endorse our general world view. If you feel the world is a cruel place where our hopes are routinely dashed - and many must legitimately think so - then films that confirm this will feel right and good. I, by contrast, believe we're born innocent, and long to be loved, and that all the evil in the world comes from the lack of love. There are very few intelligent films these days that speak to my convictions. There are very many false and sentimental films with unearned happy endings: perhaps it's in reaction to these impostors that intelligent people are drawn to assume that films celebrating misery are more true. But I beg to differ. 'Feel-good' can also be true: it's just a lot harder to do.