Directed by Bobcat Goldthwait. Starring Robin Williams, Daryl Sabara, Alexie Gilmore, Evan Martin, Henry Simmons 16 cert, Cineworld, Dublin, 99 min

IT'S IMPOSSIBLE not to read the words "Robin Williams" above the title World's Greatest Dadwithout conjuring the equally emotive "gird your loins". Surely, we gasp, they haven't made a sequel to Fathers' Day? Fear not: the name is misleading, an apposite prelude for this tremendous subversive comedy from comedian turned writer- director Bobcat Goldthwaite.

The film, which shares some DNA with Lionel Schriver's novel We Need to Talk About Kevinand even more with the high-school social satire Heathers, concerns Lance (Williams), a failed writer and single parent to Kyle (Daryl Sabara), a singularly obnoxious teen.

A classic Williams sad sack, Lance is already struggling with a noncommittal girlfriend (Alexie Gilmore) and dwindling numbers in his poetry class when his potty- mouthed, homophobic, porn-obsessed brat dies in an autoerotic asphyxiation accident. Could junior’s suicide note, a forgery by his traumatised father, be the start of a glittering literary career?

World's Greatest Dadis a treasury of inappropriate behaviours and downbeat jokes. In no more than 20 minutes of screen time, Kyle (thanks to a champion performance from former Spy Kidsstar Sabara) is established as one of the great horrible characters, an adolescent soulmate for South Park's Eric Cartman. Williams, meanwhile, revisits his finest dramatic moments – the smiling depressives of The World According to Garp, Dead Poet's Societyand The Night Listener– only to gleefully chew them up and spit them back through a peashooter. One scene, featuring a grieving Lance breaking down as he spots a copy of Spurters XXX, was almost enough to make us forget about RV.

Just to add to the wickedness, a cast that includes Nirvana’s Krist Novoselic play out Goldthwait’s barbed comic sensibilities over a Bruce Hornsby soundtrack. See – you may need to gird your loins after all.