Pride.

The trailer for Pride has been exciting me all week. It is sharp and clever and funny. But oddly, even though it is a brilliant trailer, it turns out to have nothing to do with the film. The film itself is so much bigger, more nuanced, more universal, and more moving. The trailer is like a snappy 1963 Motown tune: dazzling and snappy and joyful. The film is like a concept album.

It took me about twenty minutes to realise this. As the action began to deepen and unfold, and the first weepy moment hit, I felt a cognitive shift. This is not shoop boop boo wop wop; this is the human condition. All life is there. My mind opened up like a big old Russian novel. I settled happily into my seat. Something marvellous was happening.

The nuances are astonishing. The lightness of touch is pitch-perfect. The story is filled with paradox – it all happened in actual life, and everyone knows the ending, and yet there are revelations and surprises along the way which make you open your eyes and blink in astonishment.

It manages to hit the cinematic jackpot: it is glorious entertainment, with no dull moment, but it also makes you think. I shall go on thinking of it for days to come. To roll out the hoary old saw - it makes you laugh, it makes you cry – feels too cheap, although it does do both those things. It made me cry and cry; sad tears, inspired tears, what if tears, me too tears.

I went to see it because I wanted to, because it is my perfect subject and my perfect film, but I also went to see it because it was written by my friend Stephen. We have been friends for twenty years. I don’t love him more because he went and wrote a stunning piece of work. But I do feel very, very glad that he is my friend. And it’s not just because he will get a lot of admiration and worldly success. It’s because he has done something which touches the heart. Even if the film does not win all the prizes and plaudits it deserves, it exists gloriously in itself, as something lovely and touching, something authentic and true.

It has all the best of British, in this week when I am thinking of Britishness. It has an ensemble cast composed of every British actor you have ever loved, as well as one or two new faces who will become loved. It has masterclass after masterclass in understatement. There is a scene with Bill Nighy and Imelda Staunton where more is said in one silence than I could write in an entire novel. It has the light and dark of recent British history, and the staunch buggering on at which dear old Blighty excels.

Everyone is so good in it that it would be rude to pick out any single performance, but there is a tour de force from Dominic West, and something devastatingly profound from my beloved Mr Andrew Scott.

I would say go and see it anyway, because of my friend. But really I say go and see it for yourself. It will make you laugh; it will make you cry. But most of all, it will make you want to make the world a better place. Not in a preachy, po-faced sort of way, but in a sod the lot of them, disco sort of way.

If you are anything like me, it will make you remember the best beloveds who are no longer here, the dear Departeds who were cut down before their time. As I drove home through the misty Scottish hills, I thought of my friend T, whose picture sits on my desk, who died from AIDS in the cruel days when it was a death sentence. He chose me, when I was very young and very foolish, I think because he saw that there was something slightly other about me. I have never been able to make the expected choice, and for years I had to make defensive jokes about being a freak girl, to protect myself from judgement. It has taken me until these middle years to feel comfortable with difference, not to have to explain endlessly, or do a diverting, compensatory tap dance. My adored, camp old artist must have seen something of that, and I think it was why he took me under his wing, and encouraged me to write, and treated me like his own. I miss him every day, and I thought of him as I sat in that darkened cinema, looking at the flashing screen and thinking: these are my people.

Everyone will take something different from this film, and it has something for everyone. I loathe being told what to do and so I very rarely use the imperative voice. I find unsolicited advice one of the most maddening things in the world. But for once, I break this rule. Go and see Pride. Go and see it before you know too much about it. Try not to read the reviews or watch the clips. Go, and be surprised. It will surprise you. It will enchant you. It will make you want to do something in the world.

Oh, and there is a very real danger that you may never make an assumption again – about miners, gays, the Welsh, middle-aged women, leather queens, unions, or about quiet men with neat hair. About anything, really.

All that in a rattling 120 minutes. Best tenner I ever spent.