Shortly after I meet Sara Cox she wriggles under a sofa where her two dogs are trying to eat something they shouldn’t, but carries on talking in a muffled voice, apparently perfectly happy to continue the interview from the jaws of a slobbering animal. Given that we’re in a London photo studio, I could be slightly surprised by a TV and radio presenter who’s just had her hair and makeup done writhing on the floor, but as I’ve read her new memoir, Till the Cows Come Home, I’m not. And since I’ve also been listening to her brand new drivetime show on Radio 2, where she regales listeners with stories such as the time she accidentally took her daughter’s swimming costume to the pool – it turned out to be age 10, not size 10 – but stuffed herself into it to save a wasted journey, this seems perfectly normal. “I don’t know if you’ve seen a pork loin with string around it in the supermarket? I’ll just leave that thought there,” as she said on air.

If you’re a woman who came of age in 1990s Britain, watching Sara Cox and her best friend Zoe Ball take over the media, presenting radio and TV shows with witty, breathless, irreverent chat, it is immensely difficult not to love her. We were gripped, watching the pair of them adventure their way on to the front page of the tabloids with a drink in one hand and a male conquest in the other – it was a whole new way of being female in public life. And while Ball was from a TV family, Coxy was straight out of working-class Bolton, having only got into media after being scouted for a bit of teenage modelling, which then led to co-hosting The Girlie Show when they found out she could talk.

Yet her memoir is not a tell-all of those Met Bar years, when the stars of 1990s London all seemed to squeeze into one small drinking hole on Park Lane, but in fact the story of the previous 20, when she grew up the youngest of five children on a 40-acre tenanted farm in Lancashire. The book is like a big warm hug, full of local characters and misadventures, as well as hard graft and slaughter, with her parents working in haulage, cleaning and pubs, as well as on the farm. It’s also almost a work of social history, despite its author being only in her 40s. I mean, perhaps there are still children who dress in chiffon costumes on Bolton carnival floats while the mams swig vodka from ornamental teacups and the confused float driver accidentally hurtles them all off down a dual carriageway, and perhaps there are still English children who herd escaped cattle while dressed in a nightie and wellies, or swap eggs for shotguns, or are allowed to walk their own dog home when it breaks into the school again, all without a mobile phone in sight. But I doubt it.

‘We’ve totally Benjamin Buttoned the entire nation and sent them back to their teens’: Sara Cox. Photograph: Alex Lake/The Observer

Coxy has written this partly as a love letter to her parents and grandparents, and so her three well-spoken children, with their very different London lives, will know where they come from. Her eldest, 14-year-old Lola, is a big reader who “just thinks it’s so mega that there’s a book with my name on it. But my biggest fear,” she says, “is that people are going to go, what makes Sara Cox think that she can write a book? Who does she think she is?”

I was a strong girl and could have battered the school bullies. But I didn’t

Given that she has a clear way with words and used to lie in her bunk bed reading Shakespeare aloud with her sister, I don’t think it’s her lyricism that’s in doubt. (In the book she describes a teenage outfit of hers “like Bet Lynch after she’d been run over by a council gritter”.) But the book’s publication has only happened to coincide with her big new job on Radio 2 – it was planned long before, when she wasn’t sure what was going on in her career. In fact, when her third child, Renee, was a baby, seven years ago, Coxy says she felt “like the squirrel with the nut at the start of Ice Age, trying to cling on to the ledge of my career. I feel like I’ve got to the top of a mountain now, like I’ve conquered it. But I’ve been working towards this for so long I’m like, crikey, God, I’ve got it! Don’t dick it up!”

During the wilderness years, she would sometimes get in a London black cab and the driver would say, “Oi, Coxy, you still on the radio?” and she’d steel herself to reply, “Yes, every Saturday night at 10pm.” She got very good at body combat workouts – “Obviously I had a lot of anger.” (She favours pilates and cycling into work nowadays.) It was Davina McCall who rescued her, even though they weren’t close then, because Davina is apparently the last person in England who can actually use a phone.

Helping hand: with Jonathan Ross, who encouraged Cox to ‘feel the fear’ during her wilderness years. Photograph: Stuart C Wilson/Getty Images

“The thing with Davina is, right, if you text her, she’ll fucking ring you. Which is really scary, because sometimes you just want to be lazy and chicken and say, “I’m feeling really shit about myself,” and you want just a nice text and some emojis back. But I think because of what she’s been through, Davina will make you confront how you’re feeling, and so you’re staring at her number coming up – and I call her Dave on my phone so it says DAVE RINGING – and you’re like, oh God…”

Davina put Coxy on to a life coach called Michael Heppell. He made her work on an exercise where you imagine segments of a beach ball as the fundamental aspects of your life. She told him about her husband, Ben Cyzer, who works in digital advertising. “All my happiness and support with the kids and Ben was all fully inflated,” she says. (She was married before, to the DJ Jon Carter, with whom she had her first child, “and everybody who’s been through one marriage knows that, when it works a second time, you’re just so grateful. Ben is amazing and hilarious and he’s my other half, he’s my second chance.”) But the rest of her beach ball “was like somebody had taken a steak knife to it. And then I realised that, as much as I’m ambitious and a career woman, I’d happily take that, my personal side being fully inflated, rather than being really unhappy at home but a billionaire at work.”

Ironically, it was this realisation that led to her getting her career back. Heppell also told her that men, especially, like being asked for help, so she contacted Jonathan Ross, who took her to Carluccio’s for a coffee and encouraged her to “feel the fear”, while she took notes. Richard Madeley advised, too. “He has always been really encouraging and nurturing in a non-creepy, big bro kinda way. I did then go on to constantly mither the then controller of R2 [now head of BBC music] Bob Shennan to meet for a brew. This was when I was clinging on at Radio 1. He eventually gave me a chance covering overnights and is still a supporter and a bit of a mentor.”

Up all night: at the Reading Festival in 1998, with Donna Air. Photograph: Brian Rasic/Getty Images

I wonder if her fear has its roots in the bullying she suffered at school, where two girls humiliated and hurt her on a daily basis. She writes that she’d like to travel back in time “to tell the 12-year-old me to retaliate. To push back. I was a strong girl from lugging buckets of water and bales of hay and probably could’ve battered them. But I didn’t.” (Of course, this being her, never more than two seconds from a joke, she then adds: “While I was at it, I’d also tell myself to maybe rethink the spiral perms.”)

Yet, in a delicious twist of fate, the chief bully decided to text into the BBC Radio 1 Breakfast Show years later, when Coxy was the presenter, asking for a “shout-out”. “She got her shout-out all right,” she writes, in a rare flash-forward to the noughties, “though not the one she was expecting”. She tells me that she wouldn’t do it now. “I’d be much more grown up. But it was still much more raw then. I remember feeling myself just grow in stature and power, that very second – it was like in Honey, I Blew Up the Kid. I can’t remember what I said, but I was horrible.”

That boldness would continue, with Sara Cox always taking things a little further than other BBC presenters. She got an official reprimand for wishing the Queen Mother a happy 100th birthday with, “Ah, she smells of wee, but we all love her.” (“I can’t talk about that, Sophie, please don’t,” she says, swallowing a guilty laugh. “They might have forgotten about it.”) I tell her I remember her playing Murder on the Dancefloor by Sophie Ellis-Bextor and then idly asking listeners to phone in with how they would murder that singer on the dancefloor. She is comically appalled, says it didn’t happen, then admits it probably did.

“I mean, I remember very little,” she says. In fact, this is why she didn’t write the Met Bar memoir – she says she has forgotten most of it, and that what remains would involve “a lot of back and forth with lawyers, and a lot of people hating me. I think my peak 90s moment was posing on a Harley-Davidson outside the Met Bar with Wyclef Jean. There was a lot of Donna Air and the Appleton sisters and hanging out in Essex with the Prodigy and stuff. And Zoe, of course. But I’ve got no interest in writing that at all and I don’t think anyone would want to read it apart from you.”

I am so far in disagreement I’m on the verge of offering to write it myself. Tell us what the Met Bar was like, at least.

“Really small, with a dancefloor about the size of a Jacob’s cream cracker. I did dance in there, but it was more about talking loudly over each other and wanging on and general misbehaviour. Maybe you’d get Kate Moss occasionally. And it was part of the Metropolitan Hotel so you’d also get a few confused businessmen from Stuttgart over for a conference, who were probably thinking: ‘What the fuck are these 20-odd year olds doing running around and screeching?’ But it’s kind of to be celebrated. No bugger bothers to invite me to anything nowadays, because I’m like: ‘Will it be done by eight? Is it seated?’”

And thus she has found her perfect home at Radio 2, the new headquarters of people who used to be cool but now enjoy a comfortable chair. Since January, Zoe Ball has presented the breakfast show and Sara Cox the drivetime one from 5-7pm (Steve Wright and Jo Whiley are also on the daily schedule – it’s like the whole of Radio 1 shifted across.) “We’ve totally Benjamin Buttoned the entire nation and sent them back to their teens,” she says happily. (If there was a Nobel Prize for the rapid deployment of pop culture allegories, Coxy would be its laureate.) “The first week of the show was – babies’ births and one of my marriages aside – the happiest week of my life.”

But are there still people in her world who think they’re a bit edgy, who refuse to make the leap to Radio 2?

“Oh yes, and I’ve had a few tweets from people saying: ‘OK, I’ve made the leap, you’ve got me now,’ but also from people saying they need a Radio 1.5, you know, like a panda-breeding programme where we slowly introduce them to Radio 2. But I don’t think we need it now because Radio 2 already sounds quite different from a couple of months ago.”

‘If it was up to me I’d play Beyoncé, Whitney and Minnie Riperton – just my birthing CD’: Sara Cox. Photograph: Alex Lake/The Observer

A music team decides the playlist, “but I’ve got one of their mobile numbers now, which may or may not be good for him, because suddenly I’ll text saying: ‘Please can I play the KLF with Tammy Wynette?’ and he’ll go: “Oh Christ, OK then.’ But they’ve got a tough job to do because there are so many decades of amazing music out there. If it was up to me I’d play Beyoncé, Whitney and Minnie Riperton – just my birthing CD.”

Did she use the same birthing CD for all three babies, I wonder. “Well, I swapped husbands between,” she replies breezily, “so I thought it deserved a remix at least.”

With advice like this – change your birthing CD when you change your husband – she could have filled another sort of book altogether, since other publishers have asked her to write “a wacky mum’s handbook about how to be a bit crap at being a mum”. She makes a face. “I’m not a big fan of those ‘I’ve pushed a baby through my cervix so pass me my laptop, I’m now an expert and I’m going to do a clothing range as well’ types. I hate that kind of celebby advice book. Loads of women have had babies, love, you’re not unique – there’s one right now, crowning.”

At the risk of sounding as cheesy as those publishers, I am curious about how she made her second marriage work. “We like being nice to each other and I think that’s really important in a marriage. You want to make each other happy and you want to do nice things for each other, whether it’s, you know, making a brew or being the ones to go and put the dogs away. Every weekend, he’s schlepping around, picking up the kids, driving them places and he doesn’t begrudge it, and that is just so attractive in a man. He never fails to step up.”

Besides which, their bedroom is arranged so Ben sleeps nearest the door, “which was accidental, but actually it’s brilliant because the kids get to him first if they wake up in the night. He’s the speedbump they have to get over to get to me.”

She still dreams of returning to the countryside, but he’s a born Londoner and they love their house in Willesden too much. Some years ago she walked out of a trendy London hairdressers, only to spot a big old lorry trying to navigate a tight bend in Fitzrovia. Having spent every school holiday accompanying her dad on his delivery wagon (where they would listen in hushed reverence to Radio 2), she found herself directing this driver, using hand signals, shouting out, “To me, to me, whoa,” until she’d got him round the corner. “It never leaves you. I take these tiny dogs for a walk but, in my head, I’m getting a horse in from the field. I’m always trying to get back towards some sort of farm-type life. Always trying to swim upstream.”

Spread your wings – and fall

In this extract from her book, Sara Cox comes down to earth with a bang

“Just jump!” So I did. It didn’t go well. Let me explain. I was perched on the end of the loft platform in the barn on the farm where we lived. It was summer, just before haymaking when all the lovely fresh hay would be brought in by an army of pals and helpers, fuelled by tea.

Now, though, the barn was almost empty save for a few old bales on the dusty floor and a pile of half a dozen or so right next to the loft. These were to be my crash mat. All I had to do was launch myself from my position and push away from the wall, gliding majestically on to the scratchy landing below. It was a drop of perhaps 8ft, but to my seven-year-old mind the chasm below might as well have been the Grand Canyon. Or, seeing as this was Bolton, the “Reet Grand Canyon”.

My older sister Yvonne was the one encouraging me to jump. I was grateful that she was playing with me so I was keen to impress. As the youngest of five I was used to being a walking, talking booby prize to my older siblings. An unwelcome addition.

Early years: Sara Cox on her family’s farm.

Back then I was half girl, half forehead – a trait that was a target for classmates, both figuratively, with a plethora of nicknames (slaphead, fivehead, fodder), and literally, as they’d heartily slap it while running past, high-fiving my fivehead. So the fact my sister had agreed to hang out with me and my forehead was a big deal. Sure, the downside was she wanted me to jump to certain death for her own amusement, but at least I’d die knowing I wasn’t a chicken.

I took a deep breath. I jumped. I didn’t push away from the platform, though, I sort of nudged my bottom over the edge, so instead of springing away from the wall I slid down it like a blob of custard dripping down a kitchen tile.

In fact, I stuck so closely to the wall that I didn’t even make it on to the bales below but tumbled between them and the wall, like a lost mitten down the back of a radiator. I looked up to see my sister’s horrified face frozen in a grimace – part sympathy, part worry in case I grassed her up to Mum.

The good news was I didn’t die. The only evidence of my misjudged jump was the two red raw tramlines down my back that made me look like I’d been mowed down by a joyrider in a Silver Cross pram.

Extracted from Till the Cows Come Home (Hodder & Stoughton, £18.99). Buy a copy for £16.71 at guardianbookshop.com

• Sara Cox wears Jumper by bellafreud.com; Shirt by equipmentfr.com; Necklaces her own. Styling by Bemi Shaw. Hair and makeup by Aimee Adams using L’Occitane and Bare Minerals