Brian and Charles is a sweetly funny mockumentary about a lonely Welsh inventor who is not that good at inventing. That said, I reckon his ‘pine cone bag’ would sell pretty well if Vivienne Westwood got behind it. (His ‘trawler fishing net shoes’ would, admittedly, be a tougher proposition.) Then, more by accident than design, he manages to invent a robot, and a friendship develops between the two. This film won the Audience Award at the Sundance Film Festival, and while it doesn’t invent much itself – it is essentially Wallace & Gromit in spirit – it is still loveable beyond all measure.

The film is directed by Jim Archer and written by David Earl and Chris Hayward, based on Earl and Hayward’s short film of the same name which, in turn, was based on a stand-up routine. Earl plays Brian who lives in north Wales in a muddy rundown cottage stuffed with junk. He is completely isolated with, most heartbreakingly, a ‘Brian vs Brian’ darts scoreboard – I wonder who wins? – and is feeling especially low after a harsh winter. ‘I struggled but then I thought to myself: “Come on, Brian, time to give yourself a kick up the bottom.’’’ Quite why he’s being followed by a documentary team is unexplained. Anyway, he refocuses on his inventions, like the grandfather clock that will fly over the village to tell everyone the time. That this device doesn’t get off the ground goes without saying. Then one day he comes across a mannequin’s head in a pile of fly-tipped rubbish, which gives him the idea to make a robot companion. The robot, who will call himself ‘Charles Petrescu’, is wonderfully inelegant. He’s over 7ft tall and is basically a one-eyed plastic head rising from an old washing machine with odd gardening gloves for hands and a sartorial style that put me in mind of Sir Patrick Moore. He is played by Hayward manipulating the head from inside a cardboard box. Yet we somehow buy it. (Sit on that, CGI!)

Charles comes to life one night during a storm, Frankenstein-style, and speaks in an automated synthesised voice that is quite posh. He is happy, childlike – they’re both childlike, in fact – and curious. ‘Does the outside stop at the tree?’ he asks, when Brian, who is protective, finally allows him outdoors. He also dances, is excellent at darts and loves cabbage. ‘What are we doing? Just boiling cabbages and hanging out,’ Brian tells the documentary crew.

As I said, the film doesn’t invent much itself. The mockumentary conceit, which weirdly disappears halfway through, is familiar; and there are plenty of films about friendships with robots. As for the subplots, they hit the gentle well-worn beats that wouldn’t be amiss in a cosy Sunday-night television drama. Will Brian see off the local bullies? Will Brian embark on a romance with Hazel (Louise Brealey) from the village, who is just as shy as he is? But it somehow lives and breathes just as Charles somehow lives and breathes. (He now has an actual Twitter account, @CharlesPetrescu; I’m following him!) He is so touching, even when he presses for more independence and Brian has to treat him like a teenager: ‘You will not walk to the village. You will come in my truck or not at all!’

This isn’t a film that interrogates the relationship between man and (old washing) machine. It’s not Blade Runner or A.I. Artificial Intelligence. It has no lofty intentions whatsoever. It wants only to be a goofy non-taxing delight, which it is, and it comes in at 90 minutes, which is scant by today’s standards, but ideal, and do stay for the credits. They’re a hoot.