It’s one of the great chat-show insurgencies since Rod Hull and Emu savaged Michael Parkinson. The comedian Michael McIntyre has wrested control of Lunch with the Hamiltons, the latest showbiz vehicle for the notorious Neil and Christine Hamilton.

Having sat watching Neil’s awkward pretence of dapper suavity, McIntyre comes on stage and delivers a spot-on physical parody. After a while, Neil bristles at McIntyre’s antics. “There is such a thing as subtlety,” says Neil. “You can look it up in the dictionary.” Miaow. But McIntyre is having too much fun to stop, even uttering the greatest heresy you can ever hear on a chat show: “I don’t want to promote my show.” Fabulous. It’s only a shame that fewer than 200 of us were there to see it.

Fringe chat shows are a growth industry. This year there are five of them, all promising top acts with fairly famous hosts. For us the punters it’s a chance to sample a few acts in a convivial setting. For the hosts it’s a chance to show what they’ve got. Or, as Stephen K. Amos puts it at his show: “Television! I want to be on television!”

From the Hamiltons at lunchtime to Amos around midnight, you can spend most of a day watching stand-up comics sit down. I decided to do just that – and to see if the new Parkinson is ready for the industry types to snap up when they hit town for the TV festival this weekend.

The Hamiltons are shameless. We know it, they know it, they know that we know it, and everyone can relax a bit, safe in the knowledge that we’re all wasting our time together. So, surprisingly, their show – with Neil bobbing around the Chesterfield sofa, pouring bubbly, occasionally daring to interrupt Christine – is a bit of a guilty pleasure. True, a guest may have to sweat a bit to get this tangerine-clad two-some to stop talking about themselves. Tameka Empson and Dillie Keane both have to beg for some attention from their hosts. It all ends with four members of the audience wrapping the guests in toilet paper. So it’s dispensable at best, decadent at worst. I had fun.

As I drift into Glaswegian comedian Janey Godley’s 5pm chat show, the atmosphere is rather less gay. Godley and her guests – the journalist Jon Ronson, the comedian Johnny Sorrow and the Bullseye legend Jim Bowen – sit on black swivel chairs under blue light. They look ghostly. The mikes keep dying on them. Sorrow’s nonjokes keep dying on him. Good job there’s only about 50 of us there.

Godley is a good-natured, naturally gabby host. Ronson is on good form. Bowen is sunk in his chair looking like he would rather be filling in Ken Dodd’s tax return. Acts don’t get paid to go on these shows – they’re there to sell their wares – and this is going to do doodly-squat to fill Bowen’s room. “You can’t beat a bit of Bully,” he grunts. There’s a cheer. Bowen looks more depressed than ever. He tells a joke from Bernard Manning’s funeral. Things perk up.

At 83, Nicholas Parsons is the grand old man of Fringe chat. He’s an enthusiast, going to see every act before they appear on his show. He’s also, under his dapper charm, tough as old boots. His first guest, the comedian Micky Flanagan, opts to mock his host. A mistake. “You’re sending me up,” says Parsons, “that’s what I set myself up for,” before reminding Flanagan that his barb didn’t get a laugh. Still, he’s gent enough to wonder why Flanagan isn’t on the small screen: “Wouldn’t it be nice to get some reasonably nice people back on the television?” he appeals to the crowd. At least, I think it was Flanagan he was talking about.

Having spent his career as a foil, this is Parsons’s chance to shine. Much of the Australian musical trio Tripod’s time on stage is taken up with listening to him talk about appearing on Doctor Who, then an anecdote about Lionel Blair, of whom they have not heard. “Well, thanks for coming on the show, Nicholas,” says Tripod’s lead singer, Scod, finally.

Into the evening, and the producers of Tommy Sheridan’s show have overestimated the Glaswegian Socialist’s cult appeal. Sheridan performs with commendable conviction to his quarter-full room. But it’s politics, not light entertainment, that engages him.

His guests are Gail Sheridan (his wife), the comedian Des Clarke (his script adviser) and the comedian Reginald D. Hunter, who looks as if he is wondering what he did in a previous life to end up here.

When Gail talks about how she’d leave Tommy for George Clooney, Hunter asks her, apparently serious, if she’s really that superficial. It’s not a merry vibe. “Solidarity!” declares Sheridan finally as the show ends.

Of all the chat-show hosts on the Fringe, Stephen K. Amos is the least likely to burden his guests with stories about himself. Playing late at night in the same room as Sheridan, he’s deft and likeable but is visibly working hard to keep the chat rolling along. “You’re doing better than Tommy Sheridan,” the comedian Paul Sinha reassures him.

Michael McIntyre (fewer fireworks this time) and the fabulous Japanese comedy duo Gamarjobat fill out the bill.

This late at night, to a younger, boozier crowd, the middle-aged format feels like more of an imposition. Still, it’s defty done and largely unembarrassing. All of which is really rather contrary to the amiably awkward spirit of the Fringe chat show.

Lunch with the Hamiltons, Pleasance Dome (0131-556 6550). Janey Godley’s Chat Show, The Green Room (0131-220 0085). Nicholas Parsons’s Happy Hour, Pleasance Courtyard. The Tommy Sheridan Chat Show, Gilded Balloon (0131-668 1633). Stephen K. Amos – Weekend Talk Show, Gilded Balloon.

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