Paul Whitehouse and Charlie Higson's spoof phone-in Down the Line is easily one of the funniest Radio 4 shows since On the Hour, and the former Fast Showees bring its inane host Gary Bellamy (Rhys Thomas) to life as he travels around the country meeting ordinary Britons. Rather than the satire of its Radio 4-bear, the set-up is essentially an excuse for Fast Show-like sketches as Bellamy meets assorted listeners/weirdos played by Paul, Charlie, Simon Day, Felix Dexter and co. It's almost very good, but not yet as sharp as the original show.

In 2006 a new late-night phone-in on Radio 4 prompted a slew of complaints from listeners. It emerged that Down the Line, hosted by the bland yet "award winning" Gary Bellamy, was no dumbed-down phone-in, but a loving spoof engineered by Fast Show creators Charlie Higson and Paul Whitehouse, who voiced many of the show's bizarrely believable callers. Three series later they've found a way to bring their caricatures to TV, while at the same time gently mocking those celebrity-travels-around Britain series.

Bellamy (Rhys Thomas) sets off around the country to meet his public, from Higson's senior citizen Humphrey Milner ("Oh, I've brought you into the wrong room!") and boisterous "Lion of Harlesden" Early D (a lovely turn from Felix Dexter) to ageing "60s bad boy" Ian Craig-Oldman (classic Whitehouse). The comedy lies in the sweetly pitched mannerisms and absurdities: not a lot happens, but it happens hilariously. Credit to Thomas, too: a straight man of the old school, he manages to make everyone around him funnier.

It's not The Fast Show and nor does it try to be, but this new series, a spin-off from Radio 4's award-winning spoof phone-in Down The Line, finds Paul Whitehouse and Charlie Higson back together on TV for the first time in a decade, with their old mucker Simon Day also popping up in some of the sketches.

The Bellamy of the title is radio host Gary (Rhys Thomas), who sets off on a trip around the UK, encountering all kinds of bizarre, eccentric characters - many of whom, of course, look naggingly familiar.

They include a celebrity criminal, a 23-stone bed-ridden man, and a pair of posh sisters with decidedly dubious political views. Other top comic talents putting in an appearance include Lucy Montgomery, Rosie Cavaliero and Felix Dexter.

Ten years after their last television outing together in The Last Ever Fast Show, Paul Whitehouse, Charlie Higson and Simon Day reunite for an ingenious and amiable new series of comedy character sketches. This time, they've added an extra comic dimension to their world of mouthy plasterers, former armed robbers and upper-class loons. All the characters here are avid listeners to a fictional radio programme hosted by an unworldly, feckless DJ, Gary Bellamy (Rhys Thomas).

With the kind of cringe-making narration that adorns many a celebrity-presented documentary ("Modern Britain is a sometimes bewildering mix of different cultures and too often we don't make the effort to find out what we really think about each other"), Bellamy travels the nation to meet his fans and paint a portrait of "the United Kingdom of Great Britain and Northern Ireland". There's 23-stone Graham Downes (Whitehouse) from Harlow, who surfs the net from bed: "Out there in cyberspace, you see, Gary, I can become weightless." Higson is excellent as a doddery Cirencester gent, Humphrey Milner, playing him with eerie realism. And Whitehouse is peerless both as a potty, Sloaney rock impresario called Ian Craig-Oldman, and as opinionated Martin Hole, a Page 3-loving decorator whose catchphrase is just waiting to worm its way into our daily parlance: "I done you there. I done you right up." It's an impressive new home for the comic brilliance of The Fast Show.

Charlie Higson on Bellamy's People

Comedian Charlie Higson talks to Benji Wilson about his satirical new comedy series which he created with Fast Show colleague Paul Whitehouse.

Bellamy's People: The celebrity road trip gets skewered

Paul Whitehouse and Charlie Higson have adapted their hugely popular radio satire about a spoof phone-in for the small screen. The character-comedy masters tell James Rampton how they did it.

A couple of years ago, Radio 4 listeners were outraged to hear a phone-in shock jock, Gary Bellamy, and his motley crew of callers turn up on their hallowed station. No need for panic: it turned out to be Charlie Higson, Paul Whitehouse and various friends riffing as characters from posh Nazis to traffic wardens - the kind of social satire that gave us Loadsamoney. Now it's hitting the telly as Bellamy's People, a mockumentary in which Bellamy joins the legions of other documentary presenters clogging Britain's roads in search of a TV series. Comes with its own spoof behind-the-scenes footage. The best scene: Bellamy trying to interview Muslims.

You need to watch QI. I don't know if you know it at all, it's been around for a while in England. Stephen Fry's the host, Alan Davies is the permanent guest star and there's a rotating panel of famous people whose qualification for being on is they're amusing. Or Quite Interesting, which is what QI stands for. It's really just people talking shit. Tonight they're Rob Brydon, Andy Hamilton and Charlie Higson. I only really know Rob Brydon, and I love him. He's in Gavin & Stacey at the moment, it was on UKTV last night, he plays Bryn, Stacey's uncle. The topics on QI are letters from the alphabet, we're up to the Fs at this point, a fair way into the series. But it's a loose half hour. Tonight includes James Bond's job, Mick Jagger's walk, Bert Ward's post-Batman and Robin career in porn, and flags. Quite a lot about flags - extremely entertaining and mindless, just what you need during stressful times of (insert source of personal worry here). Even the buzzers are good - Andy Hamilton's is the Captain Pugwash music.

Behind the scenes: Bellamy's People

Following their Radio 4 comedy, Charlie Higson and Paul Whitehouse took the show's weird and wonderful characters on a road trip across Britain.

Meanwhile, anyone who tunes in to Radio 5 Live will recognise the absurdity of many phone-in programmes, and regular listeners to Radio 4 will have heard Down The Line, the phone-in spoof masterminded by Fast Show-ers Paul Whitehouse, Charlie Higson and Simon Day, which starred Rhys Thomas as host Gary Bellamy. Listeners to both will know how close to reality Down The Line's absurdist take on the phone-in format and its listeners is. And also how funny it was - a Berkshire racist ringing in says after a reference to Ebony & Ivory, "we just call that Ivory in our house". Thankfully - for anyone who's ever had the displeasure of watching Jeremy Kyle et al - Gary is meeting the public face-to-face as he travels around the country to chat to his deranged callers.