I am loathe to say it, because it is the hoariest old cliché in the reviewers book. But there is a touch of “that posh bloke what bought new duds” about Primer. The reviews all state how fascinating this tricksy little science fiction time travel tale is. They are particularly keen on the obfuscating overlapping dialogue, the very matter-of-factness about the film and the nested conundrums in conundrums. Many reviews even say that you need to see it a couple of times to understand it.

So have they? It seems a bit strange for a film reviewer, whose job it is to review films, to go and see a film lots of times just to understand it. Surely understanding might be something we demand from our first viewing. It’s a line I trotted out after seeing it, and feeling slightly underwhelmed. It was not technically very interesting at all, and I did not understand the ending. I think I just about understood the middle. To be fair the trailer baffled me.

Now I like science fiction. I have read an awful lot. So much so that I am aware that stories which have time travel at the heart of them are nearly always disappointing tricks. (Out of the “time-travel” stories I would take those where a time machine is just a way of getting to the setting, so The Time Machine and most of Doctor Who is safe.) You can get bogged down with paradoxes, what ifs and hypotheticals – and the human drama is usually destroyed. You might say that at the heart of Primer is the simple matter of trust, between two time-travelling friends who find that with this enormous power to change things they cannot trust each other. But then equally we have been given no reason to trust the film, these changes happen retroactively to the viewer, and seem somewhat implausible in the process. Even if they actually happened.

What is nice about Primer, and what most reviewers have flagged up, is that it is a film that makes you think and concentrate while watching it. Concentrate in case you miss something key, think to make you realise it. Now perhaps I am being arrogant in saying that I think there is nothing to be worked out. The loose ends are due to a loose beginning and an equally loose middle. Maybe Primer is exactly what it says it is, a first go at a film, with which future, better films will be made. Undercoat if you will: which this “posh bloke” is not wearing.