Yes, Prime Minister, Festival Theatre, Chichester

(MANUEL HARLAN)

In the early days of a new hung parliament, the Prime Minister is beset by myriad problems: the cabinet is split, the national debt is rising, the Lancaster House convention is a catastrophe and the new oil pipeline deal with Kumranistan depends on the Turks joining the EU. There's worse to come: the pipeline deal, and a huge dollar loan, further hinges on the material whims of the Kumranistan foreign minister, a weekend guest at Chequers, being properly indulged. And his whim of choice is an under-age sexual partner for the night. "Is he gay?" asks an aide. "If only it were that simple," shoots back the PM.

The PM, of course, is Jim Hacker, resurrected by the Yes Minister authors Antony Jay and Jonathan Lynn (who also directs), and embodied by a mustachioed, thin-on-top, plosiveDavid Haig, for a new stage play that owes less to their stylish half-hour comedy series than the collected works of Ray Cooney, with added complications.

The under-age sex theme is calculated to rock the Chichester audience as much as to expose the lengths to which politicians might go in order to justify immoral actions. But the chill air of bad taste and perversion is a dampener to farce, which must always seem innocently lunatic, unless it's French farce, and that only stretches to adultery.

Still, the sight of David Haig bending his body into self-justifying contortions is indeed one for sore eyes, and his outbursts are occasionally vintage: "I don't know what else I don't know, do you know?" he cries at a moment of utter bafflement, and when it's suggested that he might intervene with the cook's daughter, who is threatening to bleat to the Daily Mail, he literally combusts, Gordon Brown-style: "I don't talk to ordinary people unless there's an election going on."

We never see the cook (an illegal immigrant), or her daughter, or indeed the Kumranistan foreign minister. But the oak-panelled, book-lined Chequers sitting room is also occupied by familiar characters: Henry Goodman's silkenly superior Sir Humphrey only falters when it emerges that he's advising a bank to buy up euros big-time in exchange for a directorship he's lined up. While Jonathan Slinger's brilliantly febrile Bernard, Jim's jumpy Principal Private Secretary, smooths over the cracks with impenetrable Latin tags.

There are several plot-lines that result in more of a pile-up than a happy fusion, as we leap from the economic crisis to the logistics of finding a call-girl on a Friday night and an argy-bargy with the Director-General of the BBC (William Chubb) – who happens to call by for a drink and is urged by the PM to sell off the commercial channels and reduce the licence fee by 80 per cent – to human rights and global warming.

The play doesn't seem dated in its analysis of relationships between politicians and the Civil Service. There's even a new special policy adviser (Emily Joyce) who liaises more directly with the outside world and produces a document that saves Jim's bacon in the closing live television interview with a spot-on Jeremy Paxman impersonator.

To 5 June (01243 781312; Cft.org.uk)