You have written four screenplays: Fever Pitch, An Education, Wild and Brooklyn. What lessons have you learned over time about how to do it?
The hardest thing – compared to writing novels – is to keep yourself up throughout the process because it is so long and so dispiriting and there is never any sign of an end product. You spend an awful lot of time, if you have another job, thinking: what is the point of this? And then things get made and turn out well and you think: gosh, that was the point.

Is the technique of writing for the screen about less-is-more, showing rather than telling?
Screenwriting is about condensing. But I like writing dialogue and minor characters are fun. There is an intertwining of commercial need with art: producers always want to “cast up”. If you can find room for a Jim Broadbent or a Julie Walters [playing minor roles in Brooklyn], it will boost the film’s commercial prospects. It is joyous to look at a minor character and wonder how he or she can become more major.

Is adapting from a novel you did not write like picking up a foreign language – do you try to catch the tone of the book?
Brooklyn and Wild spoke to a readership. There is no point alienating that readership just because you have seen something in the book that could make a movie. It is too disappointing for people. Brooklyn is a beautiful, literary novel but we had to amplify it because its feelings and gestures are so understated. Colm Tóibín sees to it that the reader has to make up his or her own mind about what happened.

Artistically speaking, you are starting to get a reputation as a ladies man: you made your name writing about lads stuff – football, nerdy music buffs – but now are focusing on women. Is writing about women harder than writing about men?
I find it hard to write about anybody who is not myself (laughs). The easiest thing to write was Fever Pitch because it was a memoir. Whether I am writing about a man or woman makes no difference in terms of difficulty.

Brooklyn raises the question: how much are people’s romantic choices governed by chance?
It is always chance that one meets someone. What’s extraordinary is that young people are doing everything they can to minimise chance in their romantic lives. When it comes to looks, interests, things that can be judged on social media, there is all this flicking through pages and pages on dating websites and suddenly deciding: this is the person. Our pool was pretty small by comparison.

It is amazing any of us have survived!
Yes, exactly. Yet think how small the Beatles pool was – meeting each other, I mean. They were just four local boys. Now, you would go on the internet to find your drummer. The Beatles would not have been the Beatles…

Are you embarking on a new novel?
No…

Have you ever had writer’s block?
Writing is about confidence and wondering what the point of anything is. Wearing several hats has prevented me from being stuck. And when films get to later stages, when [Brooklyn director] John Crowley says, “We need this scene to be shorter” or “We need these people to do this to get there”, it is hard to be stuck. It’s a relief to have someone else taking those decisions.

Do you like the collaboration of film as opposed to solitary novel writing?
Next year will be the 25th anniversary of sitting on my own in a room. Any chance I can find to work with somebody else I will take.

Do you believe in fate?
I believe in fate… once it has happened. With Brooklyn, one of the most remarkable things is that when I started writing the screenplay, Saoirse Ronan was 16 and couldn’t have played the lead. And it now seems as if, through all the terrible attempts to raise funds, which crashed over and over again, we were just waiting for Saoirse to get older. I can’t imagine anyone else in the world playing that part.

That sounds like the feeling when you have met and married somebody, you can’t imagine it being anyone else?
Yes, exactly.

There is a lot of humour in the film and a particularly charming scene in which the heroine has a lesson in spaghetti-eating. How nifty are you with the long spaghetti?
I’m not terribly good. I would be splashing the family…

You are also adapting Nina Stibbe’s book, Love, Nina, about her time working as a nanny for the London Review of Books editor Mary-Kay Wilmers. What do you make of Nina herself?
Nina is just great. She is a wonderful woman: shrewd, quite chaotic and very funny.

How much has middle age changed your writing?
You look at your early things and realise you could not write them now. If I were to write Fever Pitch now, it would be older, wiser and more boring because one of the things that made the book was its lack of perspective [laughs].

Would you be tempted to live anywhere other than London?
My domestic situation does not allow it.

Do you still get fevered about football?
Nothing has changed. My two youngest sons, 11 and 12, are obsessive Arsenal fans. Even if my interest were waning, I’d still end up going to all the games.

Aside from music and football, have any new obsessions entered the fray?
I don’t feel the obsessive side to my character is there any more. When life gets more crowded, however obsessive you are, there tends not to be the same opportunity to explore it. Obsessions find space where there is space.

What do you do to de-stress?
I’m a great television watcher. We’re in a golden age of television. To my great surprise, I loved watching Bake Off with the family. Reality shows tend to be about deluded people who think they have talent when they don’t. But the people in Bake Off’s last weeks were fantastically talented and engaging. And because the programme has no side, there were no self-obsessed harpies or arses.

What will you do to celebrate your 25th anniversary as a writer?
[Laughs] I’ll have a Tesco sandwich and go to the gym.

Brooklyn is released 6 November