The Pirates of the Caribbean series has now reached its fourth instalment, On Stranger Tides, and could plausibly run until the end of the world is merely a distant memory in a cockroach's mind. These sluggish entertainments (shouldn't light-hearted material actually feel light?) have taught us that it's possible to have too much of a not very good thing. When the original film opened in 2003, it received a justifiably warm reception. How refreshing to find a blockbuster that, in doffing its tricorn to the knockabout horror of old Abbott and Costello comedies and the zestiness of Errol Flynn swashbucklers, acknowledged cinema might possibly have existed before Star Wars. There was also widespread relief that the first movie to be based on a theme-park ride had at least turned out to be more fun than queuing in the rain for three hours at Disneyland Paris.
But the most attractive item in that film's credit column was Johnny Depp as Captain Jack Sparrow, the shambolic cockney buccaneer who dressed like an explosion in an Oxfam shop and appeared to have been marinated in Pusser's rum. His jumped-up comic-relief shtick elevated the picture, but gave Disney executives the jitters. Depp has revealed that his paymasters asked of Captain Jack: "What's wrong with him? Is he, you know, like some kind of weird simpleton? Is he drunk? By the way, is he gay?" The studio head complained he was ruining the movie.
On the contrary, Depp was its sine qua non. That goes triple for the three despondent sequels. It's not uncommon for character actors to steal a picture; in a way, it's their job to be nutty and diverting while the pin-ups (Keira Knightley and Orlando Bloom in all but the new film) project unthreatening prettiness. But never before has an entire franchise, amounting to nearly ten hours of screen time, pivoted so transparently on the talents of one eccentric performer.
While everything around him, from sets to performances to swooping camerawork, is scaled so as to be visible from space, Depp fosters a conspiratorial relationship with the audience. He communicates in barely perceptible gestures - a narrowing of the eyes, a twitch of the wrist, an "ooh-get-her" pout. His near-incomprehensible line readings suggest a deluded drunk playing sober (even though a drop of booze never passes his lips in On Stranger Tides); they force us to lean in close as though receiving the whispered confidences of a demented friend. He maintains the illusion that this intimate lunacy is intended solely for us, and has been smuggled into the film under the director's nose.
All of which is a roundabout way of saying that Pirates of the Caribbean: On Stranger Tides has precisely the same highs (everything Depp does) and lows (everything else) as its predecessors. Like them, it is as indulgent and over-extended as a five-mile éclair. On the plus side, it features a raucous opening section in which Captain Jack gets to pose as a judge in robe and horsehair wig, engineer some daft slapstick business with a choux bun and a chandelier, address George II as "Your Heiny" and enjoy a passing clinch with Judi Dench, whose solitary line of dialogue ("Is that all?") echoes the audience's reaction to her cameo appearance.
The plot hinges on a search for the fountain of youth by the pirate Blackbeard (Ian McShane) and his daughter Angelica (Penélope Cruz), who have kidnapped and enslaved the chagrined Captain Jack: "There's binna norrible mishtake," he slurs, flapping shirtsleeves as abundant as a queen's bed-sheets. The moment in the third movie, At World's End, in which Jack was shown arguing with multiple incarnations of himself in a void, felt almost too self-referential, as though the film-makers were finally conceding that Depp was all we ever wanted anyway. Coming a close second in the plot-device-as-inadvertent-commentary stakes is the fountain of youth: a series that has greatly exceeded its natural lifespan is now focusing on characters trying to exceed their natural lifespan. I seem not to have mentioned that the film is also in 3-D. Like it matters.