Congratulations, Alfonso, Roma is our No 1 film of the year. How does that make you feel?
Oh, fantastic! That’s so great! From the Guardian – that’s huge! That makes me feel so happy.

How would you describe Roma?
It’s a year in the life of a family and a country … For me, this film has always been difficult to describe. It was a process of following the character of Cleo [the maid to a middle-class family, based on his own] and through her exploring wounds that were personal – family wounds. Then I realised these were wounds that I shared with many people in Mexico. And then I came to the conclusion that they are wounds shared by humanity.

Roma is a love letter to your family’s maid, Libo. What does she think of it?
She has seen it two or three times. She likes it a lot. She cries a lot. The beautiful thing is that when she cries it’s not because of what is happening to her, it’s because she’s concerned about the children. She’s not focusing on her own pain.

Your mother and father are significant figures in Roma. Have they seen it?
No. My dad passed three years ago and my mum passed early this year. I showed her a cut of the film. It was clear that her end was coming, so I organised a screening of the work in process for her, Libo and my three siblings. When your parents are gone, you start to see things differently. You can start romanticising it, or you go to the other way. For me, it’s more the latter.

The way you capture the wonder of childhood reminds me of directors such as Víctor Erice and Steven Spielberg. Were you influenced by them?
They are in my DNA. Film-makers who have this childlike sense of wonder. Spielberg has been a big influence on my generation. I love him. Erice’s Spirit of the Beehive is a masterpiece – one of those great films about childhood. Guillermo del Toro is also passionate about this film.

A scene in Roma where the father parks his car in the garage and the children watch with awe reminds me of the UFO landing in Close Encounters. Was that deliberate?
Hahahhaha! That is so funny. I never thought of that, but I can see it. Actually, that scene is inspired by the arrival on the moon of the spaceship in 2001: A Space Odyssey.

Is it true you despaired of finding the right Cleo?
Yes, we cast for almost a year, and I couldn’t the right person. Sometimes, I’d meet women who looked like Libo, but they wouldn’t feel like her. Or sometimes I’d meet people who felt like Libo, but they didn’t look like her. I was so lucky when I met Yalitza Aparicio. It was such an immediate impression. With Yalitza, there was this amazing sense of familiarity; this mix of intelligence and warmth. Then I was anxious because Yalitza said she was not interested, so there were another couple of weeks of sweating until she said yes.

How important was it that Cleo was not played by a professional actor?
I didn’t mind if she was professional or not professional. I just wanted them to look alike and be alike. But there was something studied – jaded, even – about the professional actors I interviewed for Cleo. Yalitza didn’t have any of that.

None of the actors were shown the script. Did you feel bad about not telling Yalitza in advance about the scene in which she gives birth to a stillborn baby?
Yes. She was sobbing and sobbing. I could not bear it any more. I rushed and embraced her and was, like: “Cut, cut, cut. I’m sorry, I’m sorry, I’m sorry.” And she was just crying and saying: “I thought you were going to bring a live baby.” I asked her later if she thought we went too far, and she said: “I understood why you did it, but it was very shocking.” Yalitza was sharing with us a real reaction to the circumstance. She was extraordinary.

Were you influenced by Ken Loach in withholding the script?
Look, you talk about Spielberg, Loach, Erice. All those guys are in my DNA. This is the first film I tried to do without any sense of influence, and the first film [in which] I consciously tried not to pay homage or do anything derivative. So much so that if I found myself doing a shot that reminded me of another film, I would change it. The production designer, Eugenio Caballero, more than once, asked: “Why are you changing the shot? That was beautiful,” and I’d say: “Yes, it’s beautiful because it’s not mine.” Then, when I took the new shot, he’d say: “But this is boring,” and I’d say: “Yes, it’s boring, but it’s mine.” In the end, it’s impossible to escape who you are. And who I am is a person who as a film-maker is infused with the DNA of other film-makers. Probably, I’m too much of a cinephile to be an auteur.

One of the boys in Roma thinks he has lived before. Is that you?
No, that’s my younger brother. He used to say, all the time: “When I was old …” I’m the boy who receives the slap from the mother [for eavesdropping].

Does it upset you that Netflix has allowed it such a limited release in cinemas, or are there big advantages of going with them?
I definitely wish it was in way more theatres. By the same token, I have more theatres playing Roma with Netflix than I would have got. Everybody else was going through the filter of black-and-white, Mexican and Spanish, and Netflix didn’t see it like that. I’m happy that it has sold out virtually every theatre showing it. It proves that the cinema experience and streaming are not incompatible. But I do believe the best place to watch a film, particularly a film like Roma, is the cinema. In Italy and Poland, we are playing in about 60 theatres. I’m just sad that in the UK, it’s not playing in that many.

Has Roma made you think differently about your childhood?
Not only my childhood; it has made me reassess many things, including my own complicity in certain situations – such as hierarchical society and the relationship between class and race that is prevalent not only in my country, but throughout the world.

What scenes do you find most personally painful in Roma?
There are many scenes. But what gave me the biggest pains were the scenes about the bubble of this middle-class family. This movie is set in 1971, and the social problems have actually got worse since then. That is really painful. Yesterday, we received good news about domestic workers, who have been campaigning for social security and to be legally protected. The judges declared it was discriminatory not to grant them those rights. What is so scary, though, is the amount of racist commentary about this on Twitter. And when Yalitza was on the cover of Vogue, you have no idea of the amount of racist comments about it. So, 1971 or 2018? The problems are even more acute today.