First Night: The Dictator, Royal Festival Hall, London

Baron Cohen's back, with jokes to make Colonel Gaddafi wince

From Charlie Chaplin's The Great Dictator to Woody Allen's Bananas, dictatorships have always been fertile comedic ground. Now Sacha Baron Cohen takes a crack with his latest creation, Admiral General Aladeen, "the last great dictator" and leader of fictional Middle Eastern country, the Republic of Wadiya. Having already offended a coalition of Palestinian militias in his last film, Brüno, it's no surprise he's turned his attentions to a character said to be loosely based on late Libyan leader Colonel Gaddafi.

Yet, as Aladeen tries to foil a plot to bring democracy to his country, Cohen proves he's an equal opportunity offender. Nothing is sacred with a jaw-dropping armoury of politically incorrect gags that use everything from rape to child abuse, decapitated heads and a wealth of bodily fluids. Hardcore Cohen fans will be relieved that he hasn't lost his edge – not least in a scene where he drops his phone inside a woman's vagina while trying to deliver her baby.

Unlike both Borat and Brüno, The Dictator is scripted (Cohen, plus a trio of scribes from Curb Your Enthusiasm) and it does miss the improvised energy that his earlier films had when "punking" unsuspecting members of the public. Instead, we get a sketchy plot of mistaken identity, after Aladeen arrives in New York to speak at the UN, only for his aide Tamir (Ben Kingsley) to have him kidnapped while he installs a goat-herder double as a puppet to sign a new democratic constitution.

From here onwards, after Aladeen escapes, he simply has to stop the signing – which he does with the help of former Wadiya citizen Nadal (Jason Mantzoukas), who swapped one regime for another and got a job in the Apple store. There's a predictable love story, involving Anna Faris' activist Zoey – whose unshaven pits and boyish appearance arms Cohen with a wealth of insults ("hairy Potter"; "lesbian hobbit").

Some visual gags work better – a mock Wii "beheading" game (with an option to replay the Munich Olympics attacks) is particularly good. And the standout sequence sees Aladeen and Nadal flying in a helicopter over Manhattan speaking in cod-Arabic, with phrases like "911" and "Empire State Building" frightening a pair of American tourists into believing they're terrorists.

Directed by Larry Charles, who helmed Borat and Brüno, The Dictator may be a lot more polished, and with a bigger budget, but it still feels formulaic. Like Borat and Brüno, we have another foreigner arriving in America, exploring his surroundings with a sidekick, and trading bigoted barbs. And we have another star playing herself (admittedly Megan Fox, prostituting herself for Aladeen, does feel like an upgrade on Pamela Anderson in Borat).

Oddly, despite the fact this is Cohen's first film that features a character not previously test-run on television, The Dictator doesn't feel quite as fresh as Cohen's previous films. What was once daring now feels a little dated – but if it's outlandish humour you want, there's no better comic actor working today.