As Rory Bremner well knows, understanding a nation's sense of satire is a good way to start understanding that nation at large. Starting with Holland and the spiky musical comedian Hans Teeuwen ("I'm once, twice, three times Hans Teeuwen!"), Bremner embarks on an unapologetically intellectual quest to take the satiric pulse of three nations (Ireland and Switzerland are to follow). Tonight's edition is smart, engrossing and - providing you've a stomach for edgy, Bill Hicks-style jokes - occasionally very funny.

The first hints came in the new slate of comedy shows unveiled last week, which revealed that Rory Bremner has been wooed over to Radio 4 for a series called Rory Bremner's International Satirists. Bremner always delivers, so this series, which takes a look at satire across the world, is a promising start.

Rory Bremner as Tony Blair ahead of Chilcot Inquiry

Tony Blair, in the guise of Rory Bremner, previewed his appearance before the Chilcot Inquiry into the Iraq War.

A four part series by comedian Zaltzman (with a little help from Rory Bremner, Bridget Christie, Lucy Montgomery and Kim Wall) examining the first 10 years of the millennium. The title is itself a joke, punning on Radio 4's predeliction for ultralong series (e.g., This Sceptered Isle). At least, I hope it's a joke...

Chain Reaction (Radio 4, Tuesdays, 6.30pm) has been the highlight of my late-summer listening. Through it I've come to like Frank Skinner, discovered that Eddie Izzard can still throw aside the ponderous trappings of Hollywood semi-stardom and be himself again and found, in Alastair Campbell, a charm that he managed to hide so successfully during his years as Tony Blair's minister of propaganda. And every week I've told myself that, this time, I'll resist the temptation to write about it here and focus instead on the new.

But then last week Campbell only goes and interviews Alastair McGowan and all best intentions exit stage right. Last Tuesday's Chain Reaction was probably the best of the series so far, as McGowan gave a masterclass in how he does what he does so well. Slipping from one voice to the other, frequently during a single sentence, he analysed how they came to be. The Nerd Voice, for example, which he was already using as a generic, suddenly acquired a real-life person to attach it to: John Major. "The reason why it's the Nerd Voice," he said, "is because it's completely devoid of emotion and heart.

"Technically, it derives from the back of the throat, which is also used by Brian Perkins" - changing gear ever so slightly to become the legendary Radio 4 newsreader - "but Brian has a connection with his chest, so you have this wonderful, resonant open voice, while Major" - shifting the voice a couple of inches upwards - "is stuck in the throat, so he's cut off from feeling.

"Michael Heseltine," he continued, on a roll now, "had a fabulous oratory voice. He had a trapped 'R' and he couldn't speak properly, but when he really got going he was trapped and there was a little bit of shyness there and there really was a great power to it."

And by God he was right. So simple, and yet so intricate. "There are places the voice goes to," he summed up, "and the deeper it goes, the cooler you are."

Prompted by Campbell, McGowan gave us his Tony Blair, which derives much of its authenticity from the former PM's habit of replacing his "I" sounds with "U" sounds - "Uff the Honourable Member thunks..." but confessed himself stymied by the next PM, David Cameron: "Just sound posh and whisper."

But of course, McGowan is best-known, not for his political voices - Rory Bremner has that covered - but everything else. David Beckham, for example, is an unconfident Stuart Pearce, and when McGowan segued from one to the other you saw exactly what he meant. The same voice, but with a different man behind it.

Look, the latest series of Chain Reaction will soon be naught but a beam in the eye of memory (McGowan talks to Simon Callow today; should be interesting), and I'm going to write about something else in a minute, but there was one last McGowan moment to warm our way into winter. "I've recently discovered Neil Oliver, of The One Show," McGowan said, in Scots character, "and one thing I've noticed is that he's really passionate about everything he does, but he really has to keep his passion under control, because if he ever gets carried away with it, he's just going to turn into" - mid-sentence segue - "Billy Connolly!" The mind's ear caught the connection and thought 'I could do that.' As if.

Rory Bremner interview

For the moment, budget cuts mean Bremner is recording themed specials rather than the topical series that needs weekly recording time. People say nobody saw the financial crisis coming but he has sketches going back to 1996 in which John Bird and John Fortune lampooned the whole City culture.

Impressionist Rory Bremner and his regular collaborators John Bird and John Fortune have, arguably, become the kings of biting topical satirical comedy. And in this new three-part series, everything is fair game. MPs and their expenses, the current financial disaster and Gordon Brown's much-derided grin in the video he recently released on YouTube get the skewering they so richly deserve.

Rory Bremner and pals lampoon the likes of Gordon Ramsay and Russell Brand in a new series of the sketch show. What with the PM's manic YouTube grin, the meltdown of Britain's banking system, a couple of twerps making abusive phone calls to Manuel off Fawlty Towers and greedy MPs buying Whiskas with our hard-earned wages (eight out of 10 voters said their cats were utterly disgusted), you can't say Rory and the two Johns will be short of material for this three-parter. Superbly written and performed, this is subtitled The Last Show Before the Recovery. Oh, if only that were true.

Rory Bremner lampoons Russell Brand

Rory Bremner becomes Russell Brand, cheekily grinning by a microphone and looking uncannily like the long-haired comedian as he made his prank calls to Andrew Sachs, in his new show.

A new three-part series from Rory Bremner, John Bird and John Fortune focuses first on the economic recovery, or lack of it, as well as looking askance at Gordon Brown's frightening smile and the "Sachsgate" affair. This was recorded in advance of the full horror of the MPs' expenses scandal; that will no doubt be explored in future weeks.