The television series was never like this.

More than 20 years on, Yes, Prime Minister has been artfully updated for a national theatre tour – but with the 21st century comes a much more provocative conundrum for PM Jim Hacker to solve.

You could almost sense the discomfort in the audience when the idea of underage sex with a schoolgirl was broached.

This is the new dilemma facing Hacker (Richard McCabe). Should he condone the procurement of sex for a visiting foreign dignitary, if it leads to the signing of a vital deal which could bail out Europe?

As usual, it is patronising and arrogant top civil servant Sir Humphrey Appleby (Simon Williams) who might be able to get him out of the fix.

The speech patterns and personalities of the characters are very similar to those of Paul Eddington and Nigel Hawthorne in the hit BBC series, but the script – although penned by the same writers – seems far more gritty. There’s even a bit of swearing.

There’s just one set – a room at Chequers – and hardly any action, so you have to concentrate fairly hard on the dense dialogue. This is not a night out for someone wanting a fun, easy-to-watch show with song and dance numbers, although your attention is repaid by some neat turns-of-phrase.

“I don’t know what else I don’t know. Do you know?” the PM plaintively asks Sir Humphrey.

In this modern world of spin, writers Antony Jay and Jonathan Lynn take pot shots at everything from global warming and computer models to BBC repeats and the appointment of tsars and supremos.

Still, the performances are great, with Williams deservedly getting applause every time he finishes one of his convoluted monologues involving tricky phrases like “austerity imperatives”.

And McCabe, once he hits his stride, is very funny, especially when he impersonates Churchill.

It’s worth seeing if you were a fan of the TV series, but don’t expect it to be the same.

Yes, Prime Minister continues until Saturday.

Rating: * * * *