Victoria Mapplebeck is a British director and lecturer who has worked in film, video, VR, user-generated content, and with her personal, revelatory projects she’s shown a magic touch with a smartphone camera: she won a TV Bafta in 2019 for her iPhone short Missed Call, about her life as a single mum, working out her relationship with her teenage son and his absent dad. Now she has developed this into a tender, intimate, funny and entirely absorbing full-scale feature documentary, the title of which is a reference to the central circuit board on a computer – meaning perhaps both the importance of the digital equipment she’s using to record everything, and her own central importance to the computer of their own family unit, the motherboard that isn’t allowed to go wrong or take a day off.

Motherboard is essentially a home video love letter to her son Jim that crafts 20 years’ worth of footage, showing her own life and that of Jim growing surreally from a tiny baby into a fiercely opinionated, smart young adult who suddenly towers over the parent. The film lasts around 90 minutes, which is about how long the growing up process seems to take in real life for a parent. And at the same time she has to deal with exhaustion, a breast cancer diagnosis, anxiety and her own complex relationship with her father who walked out on the family when she was still young.

Richard Linklater’s famous time-lapse film, showing a kid growing up over three hours, was called Boyhood; Mapplebeck’s could be called Motherhood or Sonhood or Lifehood. It is confessional, and hyperlocal in its 4K-rendered detail; it is a richly satisfying, humane, sympathetic study at the end of which I felt I knew Victoria and Jim as well as if they lived next door. Mapplebeck’s camera seems always to be there, a fly on the wall of her own life: she appears dedicated – even ruthless – in her commitment to placing the camera where it can capture her, even in the most unflattering way. There is a startling, surreal shot of Mapplebeck having radiotherapy, the camera placed at her head and looking down her foreshortened body, glowing in a clinical light. She also gives us a brutally powerful confessional scene in which she says she wants to stay alive while Jim is still a child: “I don’t care when I die; I just want to see him get to adulthood.”

There is also something very touching in the insights she gets from Jim about his feelings on meeting with his dad: “I’m going to be sad; even if it goes well, I’m still going to be sad.” It’s a film that works because it doesn’t strain for anything other than its own personal record, and it has a marvellous humanity and warmth.

Motherboard screened at the Copenhagen documentary film festival