Is Bill Murray fit for sainthood? Certainly his fans have him figure as some sort of lesser divinity, maybe one of the more saturnalian Greeks or pagans, with a taste for crashing karaoke parties with a pretty Dutch girl on their arm. How else to explain his mysterious deus-ex-machina drop-ins at random points around the globe — driving golf carts around Stockholm, reading poetry to construction workers in New York, acting as roadie at a rock festival in Texas? Where else does Murray’s power of deadpan derive if not the omniscience of a melancholic and slightly bored God, trying his best to wile away eternity? That’s why his best role continues to be Groundhog Day, in which he played just that.

More recently he’s started to show up in more earthbound form. He played FDR to perfection in Hyde Park on Hudson — his voice hoisted high in imitation of FDR’s patrician drawl, head thrown back in laughter, martini glass brimming o’er with Wodehousian good cheer, Murray didn’t disappear into the role so much as disappear into the air of moonlit mischief that hung over the movie, like a twinkly master of ceremonies. In St. Vincent, he plays a cranky old codger who pads around his dilapidated suburban house in sleeveless T-shirts, a thick Boston-Irish accent and a cloud of cigarette smoke: a Bukowski slob who collects dust like it was a protected species. Murray doesn’t break character for one second, but since when was it fun to watch Murray not break anything? In rampant form, he can destroy whole movies with one look, his gaze so drained of illusion as to suggest that everything — the other actors, the film he has the ridiculously bad luck of having to appear in — is up for ridicule.

There’s none of that delicious sedition here, although he does get one great moment of ingratitude when someone cleans up his apartment: ‘Where’s my dirt?’ You could ask that of the whole movie, one of those faux-indies the studios have got better and better at fabricating, this one from the Weinsteins, the soundtrack mixing Jefferson Airplane and The National with hipsterish eclecticism, while the director Theodore Melfi favours flattish, off-centre compositions dominated by a single bright colour, with occasional bursts of slo-mo, à la Wes Anderson. (Murray’s entire performance is in slo-mo, so he barely needs it.) There is even a wheelchair race, a more-or-less compulsory means for old farts to establish their young-at-heart bona fides ever since Gene Hackman strapped himself into a go-kart in The Royal Tenenbaums.

Here, the youngster is young Oliver (Jaeden Lieberher) who moves next door with his newly single mom Maggie (Melissa McCarthy), who, working late, starts using Vincent as a babysitter. Naturally, he is soon teaching the kid how to break his classmates’ nose, taking him to the racetrack and introducing him to his pregnant Russian whore Daka (Naomi Watts), first seen playing giddy-up horsey in bed with Vincent, her pregnant belly bouncing. You can see Murray’s eyes lighting up when he first saw that lot in the script — drinking! Smoking! Whoring! Betting! — and then turning a blind eye to the frantic series of apologies issued by the script on his character’s behalf. Beneath the grungy production design beats the usual Hollywood pacemaker, jolting us with tinny redemptive beats. Not only does Vincent pay for Daka’s ultrasounds, he also tends to his Parkinson’s-afflicted wife in a nursing home; not only does he do her laundry every week, but — at a key moment in the plot — he has the decency to suffer a stroke himself, landing him with a similar set of impairments, although I prefer to think of the thick finger Murray raises to his speech therapist as his considered opinion on this section of the script.

Melissa McCarthy, Jaeden Lieberher and Naomi Watts star in St. Vincent

Such is the price paid for lionisation: sooner or later, people start viewing you as a lovable old rogue. There’s too much lovability and not enough roguishness to St. Vincent, which ends with young Oliver making a speech at his high school nominating crabby old Vincent as his neighbourhood saint. Murray wears the same sheepish grin he wore in the final reel of Groundhog Day — Gulliver being celebrated by the Lilliputians. In his head, he’s already lining up the sangrias.