“The Selfish Giant” is a beautiful, profound, perfectly acted film about two vulnerable young English boys and the havoc life wreaks upon them, that features everything to recommend it, but I can’t say you should watch it, because it is so unbearably sad that you’ll be completely sorry you started it.

Conner Chapman plays a “too real” role as the eager but rejected Arbor in “The Selfish Giant,” streaming and on DVD now.

Conner Chapman plays a “too real” role as the eager but rejected Arbor in “The Selfish Giant,” streaming and on DVD now.

The bleak and gritty setting starts you off down the path of despair, with meticulously rendered portraits of dismal family life in two different, equally depressing households. If you have kids, you’ll feel extra bad, whether you’re in the tense, single parent household of Arbor, a thin hyperactive little boy with a criminally involved drug addled teen brother, or in the “pikey” household of the more sensitive Swifty, one of seven extremely poor kids teetering on the brink of starvation.

The flawlessly realistic performances convince the viewer utterly of true suffering onscreen, particularly of the foul-mouthed young boys. Don’t try to comfort yourself that it’s just a movie; these little fellows are too real. Then, the relentless quality of the supporting cast of cruel, sad adults hammers every scene home; we never get a moments’ respite from a less authentic character, alas. Siobhan Finneran, who played the evil maid O’Brian on “Downton Abbey,” is particularly haunting; just seeing her scuttle back in her darkened house upon her drunken husband’s commands breaks your heart without a word.

No, this movie is so well-executed that we are made to believe, to our endless despair, that we are really inhabiting the bleak and dreary world of impoverished families, as Arbor and Swifty try to earn some cash by collecting scrap for a morally suspect junk man named “Kitten.” They gather various abandoned metal, but the “bright wire” copper is where the money is, and that must typically be stolen.

Gentle, intuitive Swifty garners favor from Kitten through his skill with his racehorse, leaving Arbor even wilder and more desperate than ever. I won’t ruin the ending for you, but let’s just say no one earns a college scholarship. It’s a beautiful, devastating story that I hope never to see again.