There is a great deal to love about Sarah Gavron’s new movie Rocks but, as a survey of contemporary British youth and their prospects, it is pretty depressing. Rocks is a 15-year-old London schoolgirl (played by newcomer Bukky Bakray) who is abandoned by just about everyone. Her father is dead and her depressed mother decides to go awol, leaving her to look after her younger brother unsupervised. Her school seems more concerned with lowering pupils’ expectations than educating them. Social services can barely keep track of her, either. There seem to be no safety nets left.

Realist cinema has always recognised the effectiveness of highlighting society’s failings through the plight of children, and Rocks joins a procession of British kids sounding the alarm, from Ken Loach’s Kes through Shane Meadows’s Somers Town, Andrea Arnold’s Fish Tank, Clio Barnard’s The Selfish Giant and more. The situation never seems to improve.

In fact, you can chart the decline just through Ken Loach movies. In Kes, at least poor Billy had a family, a hobby, a vaguely supportive teacher and, by today’s standards, a relatively well-resourced state support network. By the time of 2002’s Sweet Sixteen, Martin Compston’s 15-year-old is a petty criminal, living in a caravan by himself while his mother finishes her prison sentence. Last year’s Sorry We Missed You at least featured a stable nuclear family, but the pressures of modern life are tearing them apart. Dad is driven to distraction by the empty promise of the gig economy. Mum is working all the time, too, and once again, no one has much time for the kids. The son is drawn into truancy and vandalism; the daughter’s efforts to bring the family together only make matters worse.

Now children are routinely left to fend for themselves. Even in the relatively jaunty world of Netflix’s Sex Education, little is made of schoolkid Maeve living in a caravan on her own. When her useless mum returns, you understand why. Next to come is hard-hitting British drama County Lines, in which a London schoolkid is groomed by drug gangs. His single mum can’t make ends meet so, unwisely, he does. Like Rocks, County Lines is informed by what is happening in real-life Britain today.

At least we have empathic movies such as these to convey what’s going on, but Rocks is by no means bleak viewing. Quite the opposite. Its high-spirited, multi-ethnic cast (all non-professionals) look and sound like modern London teenagers. They break into song and dance, they have a laugh and, most importantly, while the grownups might have abandoned them, they look out for each other. Where there’s youth there’s always hope.