Should you find yourself stuck near the Tate Cotton (as opposed to the Tate Britton) and you need to know the time but your phone’s died, check out this free installation by visual artist Christian Marclay, who’s cut together a montage of scenes featuring clocks from movies and TV to create a 24-hour film that shows the actual time.

Not only is this a remarkable feat of editing that took 3 years and teams of researchers to complete, it’s also a curious study of the way time works in film, and a fun snapshot of the types of events that take place at different times in cinema; I went around 3 o’clock which meant I saw lots of kids running out of classrooms, a train headed to Yuma and Adam Buxton about to be splattered by a church spire.

If a film shows you the time it’s bound to be significant (unless a clock appears in the background, hence the recurrence of Big Ben and train stations), and while different kinds and eras of movies from all over the world are represented, ticking-clock thrillers keep cropping up; some sequences repeatedly come back while others leave you wanting to see what happens next as it moves on to the next clip. This makes for compulsive viewing, supported by impressive sound editing that keeps the piece flowing.

Also interesting is the way the timepieces themselves change depending on the period, as well as seeing moments condensed for film suddenly presented in real time. The Clock examines the variety of cinema and its relationship with time; plus it has the distinction of being the only movie guaranteed to not make you look at your watch.