One of the important aspects of taking out a loyalty membership at a theatre, or in this case cinema, gentle reader, is to make sure that you get your stake back in benefits, freebies, early bookings and what-have-yous. For some reason – maybe because I love live entertainment so much – it’s very easy for me to get out of the habit of going to the cinema. But I was aware it had been a while since our last visit to the Errol Flynn Filmhouse (a long while!) so I enquired when my membership was up. Two weeks’ time – and still two free films to go and see! I couldn’t let them go to waste, so I desperately scoured the listings to find a couple of films that a) were on at a convenient time and b) didn’t look too awful. And the first of those was The Shallows.

I didn’t know much about the film in advance to be honest. I knew it wasn’t a particularly long film, and that it featured beaches and the sea. Actually, I thought it was a French language film. I gathered there was to be some tension and suspense. Maybe someone would get murdered by personne or personnes unknown and get washed up on the beach. Wrong.

Here’s an idea about the plot – although I don’t want to give too much away if you haven’t seen it. Jaws meets Gravity. Let me explain: Nancy is a freewheeling sort of girl, with some slightly blurred backstory where she is finding her own way to grieve at the loss of her mother by taking a lone expedition to a beach in Mexico which is known to her family as “Mom’s beach” and to the rest of the world as… the beach with no name. In fact, whenever Nancy asks anyone the name of the beach they refuse to tell her, in a mysteriously doom-laden portentous manner. Honestly; she spends the early part of the film constantly on her smartphone, so why didn’t she just zoom in on Google Maps? I have to say that whole “what’s the name of the beach” element to the film really got on my wick.

However, once she’s there, she quickly nips out of her clothes and dons her surfing togs, because she’s nothing if not an adventure girl. There are a few lingering shots as she’s peeling off the layers and nestling into her surfboard that tread ever-so-slightly in the direction of gentle soft porn; but, to be fair, those sequences give you an impression of extreme closeness to the action (which is vital for the film to work). And, anyway, Blake Lively has a very nice bum. There’s a couple of lads out surfing as well; they suggest a threesome (not that kind of threesome) but our Nancy is more of the reflective, I Want To Be Alone, type, so she keeps her distance. And starts surfing. And I think that’s all I need to say about the plot without spoiling it for you. However, if you remember the most menacing character in Jaws and the nature of the story in Gravity – I’m sure you’ve already put two and two together and come up with a bloodstained wetsuit. The way Nancy’s plight is resolved is – shall we say – interesting; I guess that as she has been extremely unlucky with that last wave of the day, it’s only fair that she gets the jammiest, luckiest break at the end. Let’s just say that if insurers don’t pay out on Acts of God, the family of that shark are going to be financially bereft after the final credits.

It’s actually a really well put-together film. The tension starts very gradually at first; you sense something horrible is going to happen – but it doesn’t – so you allow yourself to be lulled into a false sense of security. Nancy’s reliance on her mobile phone is entertainingly and inventively captured by our seeing her phone screen just as clearly as she would see it; in fact, it monopolises one’s attention at first, just as mobiles tend to in real life. When Carlos tells her off for not looking at the beautiful scenery, it’s a reprimand to which we can all relate. Flavio Labiano’s cinematography is absolutely captivating; the action surfing scenes where the characters are caught right up in the waves are breathtakingly exciting and give you some insight into how exhilarating doing it for real must be (I’ve never surfed, nor am I ever likely to!) There are some slightly gory moments which make you cringe and look away from the screen; but a lesser film would have indulged much more in the blood and guts of the thing and less on the mental anguish of our heroine, which is a damn sight more interesting.

And Blake Lively is brilliant as Nancy; she’s hardly ever out of shot in the whole film and she really lives the role. You never for a second think of this as an acting performance; she’s there, experiencing and reacting to the whole terrifying scenario. If I were her, I’d never get in the water ever again.

Mrs Chrisparkle and I spent many of the film’s 86 minutes wincing at the screen through our fingers. As we were all leaving the cinema, the two girls to our right said they couldn’t wait to get home for a nice cuppa tea. Certainly much of the action is the stuff of nightmares, and to watch the film is physically exhausting; but when you look back you realise that it’s actually a tight and taut, well-paced thriller that keeps you on the edge of your seat and desperate for a happy ending. All that and teach-yourself suturing!