I don’t have to tell you how much of a landmark television programme Yes Minister and then Yes Prime Minister were during the 1980s. They attracted massive audiences and gilded the already glowing careers of Paul Eddington and Nigel Hawthorne. If you catch a repeat episode today, it still makes you shake with laughter, revealing hypocrisy, pricking pomposity, rescuing triumph from tragedy.

Thus the Derngate theatre was pretty much packed last night with ladies and gentlemen of a certain age and class who would have been loyal fans of the TV show. Mrs Chrisparkle was a loyal fan of the show in her youth and was probably the youngest member of the audience. No criticism here – it’s great to see a production providing something that people want to see and the concept of bums on seats is good for everyone.

The scene is Chequers – all very convincing wood panelling and bookcases; and its windows and external brickwork definitely reminded us of the walks we used to do years ago that crossed the Chequers estate when we were Bucks based. It’s a timeless location; and serves to reflect the Yes Prime Minister of the 1980s and the updated 21st century version equally well. For indeed Jim Hacker is today Prime Minister of a coalition government, facing modern issues such as the banks, global warming, and public sector cuts. It takes a leap of faith to believe that the same three people (Jim, Humphrey and Bernard) – or at least three people with the same names and jobs – are still in charge of the country thirty years on; but you accept it nonetheless.

However, the script is firmly as PC as it would be in the 1980s, if not 70s. In fact it’s one of the most xenophobic pieces I’ve come across in a long time. From the Prime Minister’s early references to wops, dagoes, micks and polacks (inter alia), through taking the rise out of our European partners, to a plot progression which suggests some perilously dire consequences for some people but it’s ok because they are only foreigners, I personally found a lot of the content a bit distasteful. This is definitely a world that has never come into contact with Ben Elton, and makes Terry Wogan’s “Johnny Foreigner” positively diplomatic.

I wondered how the production would treat the concept of bringing back much loved characters associated with much loved actors and make it work without the original cast. Would they indeed be the same characters? Would they be doing impersonations? Would they be completely different? Well, yes they are more or less the same characters, they certainly aren’t impersonations and they are somewhat different.

Simon Williams plays Sir Humphrey and he comes across as a much more benign figure than Nigel Hawthorne. You feel that he isn’t quite so devious as his 1980s counterpart, a little more aloof, a little more enjoying the luxury of power, more laid back, less Machiavellian, almost avuncular. I don’t know if Simon Williams had a cold, but his voice wasn’t very clear or powerful when we saw it and this detracted from the natural authority you associate with the role. However, he admirably coped with Sir Humphrey’s long obfuscating speeches, which twice earned him a round of applause from the appreciative audience. After the first one, I saw Richard McCabe as the PM mouth “Well done” to him.

Richard McCabe plays Jim Hacker a little more cynically than Paul Eddington – this PM is purely interested in self-preservation. All his plans are devised to secure his own political tenure, and you sense that if this causes something which is a boost to the country, that’s merely a fortunate bonus. This is perhaps a slightly more realistic updated character; but he is also more of a buffoon too, reverting to childishness when really Up Against It, and adopting a look of astonishment perhaps a little to readily.

Chris Larkin as Bernard Woolley is perhaps the most different from the TV characterisation. His Bernard is rather camp, a terribly public-school prig; and when he does his set-piece speeches which correct grammar or metaphor, he comes across as a bit of an arrogant arse whereas Derek Fowlds’ Bernard was more genuinely earnest. I didn’t get a sense of his real personality.

Whereas Simon Williams played the whole thing straight and gave it credibility, both Messrs McCabe and Larkin frequently went into pantomime mode with their facial expressions and general comic business, which felt a bit unbalanced. The two other major characters, Charlotte Lucas as Claire the policy adviser and Kevork Malikyan as the ambassador, were both very straightforward and realistic and were excellent. However, in a cameo role, Michael Fenton Stevens as the political presenter interviewing the PM on TV seemed to me to go way over the top on the stunned facial expressions, paving the way to what I felt was rather a sudden and underwhelming climax to the play.

Without doubt, there were some extremely funny sequences. I loved the Prime Minister’s prayer scene. It’s exactly how you think a PM would pray. Sir Humphrey’s script is well written and full of entertaining observations. And the biggest belly laugh of the night actually went to a prop – I’ll say no more. But the revelation of the sexual proclivities of the Kumrani Minister, whilst sharply focusing the play in the modern era, actually served to reduce the comic effect somewhat, and I did find the constant xenophobia persistently irritating.

That said, the appreciative audience laughed a lot, especially in the second half, and it was warmly received at curtain call. Maybe the overall problem with it is that it takes 2 hours 20 minutes to tell a story that 30 years ago would have been more pithily condensed into a half-hour programme. It was good, there were some laughs, but we expected more.