Venus touches on any number of themes, like our fear of growing old and the uselessness we foist on those who do – but mainly, as its title suggests, it’s a film about love. That is, it’s specifically a love story, rather than a romantic comedy: Admittedly there’s a lot of comedy in there, and even a fair bit of romance, but rom-com’s are about taking two people who are somehow meant to be together and placing obstructions in their way that they can overcome to end up together. And in Venus, not only are the obstructions pretty much insurmountable, it’s hard to say whether they should be surmounted at all.

That’s because the void that separates the lovers in this case is one of about seventy years. Peter O’Toole plays Maurice, an ageing actor whose best friend Ian (Leslie Phillips) finds himself landed with his teenage niece, Jessie, as a permanent lodger. When Jessie proves to be not the live-in nurse that Ian is hoping for but an unruly houseguest who does nothing but lounge about and drink his beer, Maurice steps in, befriending her and finding her work (of a sort) in her chosen career of modelling. But Maurice – intelligent, witty and still something of a lothario despite his accumulating years – is looking for more from Jessie than just companionship.

Through his pursuit of physical love, Maurice is trying to preserve something of himself that society is all too eager to strip away; just as through the way he dresses, the way he speaks, the types of roles he seeks, he tries to retain an identity defined by more than just how old he is. The tragedy of Venus, (and there’s a lot of tragedy here, for a film that’s been marketed as a comedy), is that he can’t hope to succeed. Most of the parts he’s offered are playing corpses, his body is failing him, and Jessie’s affection for him is nothing like the passion that he feels for her.

But, while Jessie’s responses to Maurice’s advances aren’t always positive or even very pleasant, she does at least acknowledge them, and him – and he in return treats her as someone worthy of devotion, as opposed to the casual lust and ill-treatment she’s received from men in the past. Both of them have been rejected in one way or another, neither of them fits neatly into the society around them. And it’s here that Venus really prods at bigger questions – ones that are perhaps particularly applicable to British culture, with its increasingly nervous and remiss attitude to its young and old.

But in another sense, Venus is a film about Peter O’Toole; in places, almost a homage to him. It may be that the part of Maurice was written for him, it certainly feels as if it is, and for this reason only it’s hard to agree with the suggestions that it’s his greatest performance. But it’s certainly a fine showcase of his talent, and even if he’s essentially playing himself it’s still a wide-ranging and layered portrayal. The first half is held together by O’Toole’s charm and wry comic timing, while the tragedy of later scenes hangs on his ability to look fragile and painfully world-weary – to the point where I was reminded of that footage of a desperately frail Bela Lugosi that Ed Wood inserted into Plan 9 from Outer Space.

Possibly, though, it’s Jodie Whittaker who has the more difficult part to play – Jessie is far less sympathetic, in places distinctly unlikeable, and Hanif Kureishi’s otherwise excellent script occasionally puts some stilted and unlikely soliloquies into her mouth. Whittaker handles these well, as she does deadpan comedy, but it’s a shame that Kureishi didn’t feel more confident in his ability to develop the script’s tragedy as he does its comedy – through deft, believable dialogue. Still, it’s a minor complaint; for the most part Venus is challenging, funny and moving, and a promising glint of brilliance for the revitalizing British film industry.