Mel and Sue: Can the much-loved Bake Off double act resurrect the chatshow?

They're the best thing about 'The Great British Bake Off'. Now Mel and Sue are going back to their roots with a new chat show. They talk to James Rampton about cake and critics

Sister act: Mel Giedroyc and Sue Perkins in their new daily chat show, 'Mel and Sue'

When Mel Giedroyc and Sue Perkins were first offered the job of presenting The Great British Bake Off in 2010, they weren't convinced. "We turned it down," says Perkins. Why would you want to do a show about cakes?"

The duo, who have been best friends since meeting at Cambridge University nearly three decades ago, were eventually persuaded to have a bash at The Bake Off. They had no idea what a phenomenon the show would become. "The allure was that we'd get to work together again for the first time since 2002," continues Perkins, 45. "We'd both gone through tough times. We're not the best at planning our careers."

The programme, in which Giedroyc and Perkins and the judges Mary Berry and Paul Hollywood winnow 12 amateur bakers down to one winner, has won numerous awards, including two Baftas. The finale of the last series, the first since the show's transfer from BBC2 to BBC1, netted 12.29 million viewers – unheard-of for a cookery programme and the highest figure for a non-sporting event last year. Its success has helped the pair obtain other high-profile work; Perkins recently presented the BBC2 travelogue The Mekong River, while this spring Giedroyc is hosting Relatively Clever, a new quiz show for Sky 1.

A large part of the show's appeal lies in the effortless chemistry that crackles between Giedroyc and Perkins. They have a symbiotic relationship, enjoying the easy familiarity, ceaseless mutual mickey-taking and ability to finish each other's sentences that come from 26 years of close friendship. Meeting them in their West London production office, it is obvious they go as well together as apple crumble and custard – or Baked Alaska and dustbin.

The pair are now parlaying their relationship into a new daily chat show, Mel and Sue. The guests on the first show are comedian Jennifer Saunders and choirmaster Gareth Malone. It will revive memories of their much-loved chat show, Light Lunch (subsequently rebranded Late Lunch), which ran on Channel 4 in 1997 and 1998. Giedroyc, 46, who is married to TV director Ben Morris and has two young daughters, says: "You get to know the patterns of the way someone speaks. You know when to chip in and when to stay quiet. There is a horrific over-familiarity which is second nature to us. It was there from the beginning. It's brilliant."

The pair reveal that their chat show will feature several innovations, including live calls from the public. "We will have a hotline to Paul Hollywood, Mary Berry and our mums," laughs Perkins. "The phone will be hidden underneath a casserole like in Chief O'Hara's office in Batman. Our mums would be so terse. My mum would say, 'I don't know that I like your outfit.'" There will also be a cook on every episode, but, as Perkins is quick to point out, "It won't be a celebrity chef. As on Bake Off, it's about the democratisation of brilliance. The idea that only the overpaid, designated few are capable of brilliance is ridiculous."

If fronting a daily chat show gets too much, Perkins has come up with a neat concept. "I had the idea of franchising out the Mel and Sue name, so we don't even have to be there. So one day it could be Mel Sykes and Su Pollard and the next Melvyn Hayes and Aung San Suu Kyi."

Picking up the baton, Giedroyc says: "Nobody really would care. The name would live on without us. It would be like Brad from Neighbours, who was played by three different actors. Or it could be like Doctor Who. We could do the thing at the end of the series where we lie down, go fuzzy and regenerate as Mel B and Susan Boyle or Melvyn Bragg and Sue from Sooty – that's an episode of In Our Time they've never broadcast."

Of course, this chat show might never have been commissioned but for the immense popularity of The Bake Off. So just why did the idea of a TV baking competition in a tent catch fire? "I don't know," says Perkins. "All the show consists of is us eating our way through a mountain of carbohydrates while firing off sexual innuendos. That's a specialist service that I offer as an extra in my relationships. The show is basically great fun. And as long as it's fun and the audience like it, we'll be there."

"What's not to love really?" Giedroyc chips in. "The Bake Off taps into nostalgic feelings about your mum baking in the kitchen. It's a big ruddy comfort blanket, and you get attached to the bakers. It also genuinely has a good heart."

Mel Giedroyc and Sue Perkins in their 'Light Lunch' days (ITV/REX)

Perkins, whose off-screen partner is TV presenter Anna Richardson, adds: "The timing was very good, too. It was a perfect storm. When The Bake Off first appeared, people had had enough of cynical, harder-edged TV – that theatre-of-cruelty style is quite boring. We were in the midst of recession, and it harked back to another time of recession, the 1950s, an era of make-do and mend and back to basics."

Giedroyc thinks their eagerness to avoid the more sneering attitude of many reality TV shows helped boost the popularity of The Bake Off. "At first, the show was harsher in tone. But one thing we brought to it is a sense of kindness and protecting the bakers. It's all about the bakers. Twelve bakers are whittled down to one, so it's like an Agatha Christie novel basically, but set in a patisserie. And Then There Were No Cakes, with Mary Berry as Marple and Paul Hollywood as Poirot. Sue and I are Hastings and the other one."

What's the secret to their long partnership? "It's very sisterly. We know each other as well as sisters do," says Giedroyc. "We've known each other almost as long as our own sisters. And we never bicker. We've only ever had one row – in full New Romantic costumes. I can't remember what it was even about; we were probably both in a bad mood. But I do remember that Sue was dressed as Adam Ant, and I was dressed as a member of Spandau Ballet."

"We didn't enunciate anything major," Perkins recollects. "It was more of a light seethe, swiftly followed by absolute hilarity – 'You're dressed as one of Spandau Ballet, and I'm Adam Ant.' That's the only time that it's happened in 26 years. So if you're looking for stories of rock'n'roll excess, I'm afraid you've come to the wrong place."

For all their current popularity, it has not always been cloudless skies for the double act. "We have our detractors. If we didn't, that would be weird. That would make me feel, 'Oh God, we must be really bland,'" says Giedroyc. "You have to have detractors."

"We have been out of fashion", adds Perkins. "We're not very cool. If the fad is for cool, the phone is not going to ring for us. Although Mel says she looks very cool in her hessian smock." She adds: "We both went through dark times. But our friendship has always endured, whatever the work situation."

"We're like cave-aged cheese," Giedroyc reckons. "We taste better now."

"Yes," says Perkins, taking the comic bait. "We ooze at the edges and have a slightly unpleasant odour."

Perhaps they have enjoyed success precisely because they have never taken it for granted. "I still have a sense of 'I got away with that. Someone will find me out soon.' This business is fickle. You have very good patches and less good patches, but you learn to ride them out", says Giedroyc. "As long as you don't take yourself too seriously, you'll be fine. When you lose sight of that, you're in trouble."

About their new show, Perkins says simply: "We'll have fun and hope it's contagious. Anybody who doesn't enjoy this job should be ashamed of themselves. It's an absolute gift."

"It's not like working really", says Giedroyc. "It's absurd to say that it's a job. It's just the two of us messing about."

'Mel and Sue' starts on Monday at 4pm on ITV