Here's another audience leaving War Horse.

They file out, heads down, each with one arm holding the shoulder of the person in front. They are the walking weeping; the sad led by the sobbing. It's the Odeon equivalent of that well-known First World War photograph of gassed soldiers – except this time it is emotion that has overcome them.

Well, that's an exaggeration, of course, but for those of a certain disposition, this film remains tough to get through. On the Somme of emotions, it's the frontline. Duckboards are practically needed between the rows of seats to soak up the tears.

Still, it's easier to cry in the cinema than it is at the theatre. The cinema is darker and you can let the tears falls discreetly down your cheeks without anyone noticing (apart from your daughter: "Dad? Are you crying?").

At the theatre, particularly one in which the stage juts out a little, the spotlights catch more faces and your cheeks can suddenly glisten.

There is a moment in the stage show of War Horse – and in Billy Elliot too – when his dead mother appears as her letter is read. The theatre is completely silent and everyone is caught in an invisible, taut web of poised emotion. You know that if you blink, or move your head even slightly, a mini-Niagara will start that could wash away rows P through to T.

It's no good telling yourself to get a grip, that you're an adult. These moments in shows and films are very powerful. Even now, thinking of the boy calling to the horse, it is possible to feel the little ocular taps going on.

What is it about the great dark pools that are horse's eyes? Why does the love between man and animal touch us so deeply? Is it because, like love for one's children, it is unconditional? Or is it just that teenage dogs never slam doors?

One hopes Joey, the horse, and Uggy, the terrier from The Artist, both make it to the Oscars. You can just see them parading up the red carpet, two members of staff following Joey with a bucket and shovel, while Uggy dances on his hind legs on Joey's back.

Meanwhile, as the boy continues to call to Joey in cinemas up and down the land this month, perhaps the spirits of all those poor fallen horses in northern France turn their heads, silently stamp their hoofs and remember.