When Zoe Ball was umming and aahing about whether to take the Radio 2 breakfast show gig 18 years after leaving the Radio 1 equivalent, her son Woody (not around last time) played a part in persuading her.

“He said ‘Mum, come on, don’t even think about it, it’s like the coolest thing you can do’,” Ball told Chris Evans, whose show she is taking over. “‘Be the first girl on Radio 2 breakfast, it’s amazing’. And he went ‘And Mum’ – and he looked into my eyes and he held my hand – ‘someone will listen’.”

It wasn’t 100% encouragement at home. Ball asked Nelly, her eight-year-old daughter who listens to Greg James on Radio 1 in the morning, if she would be making the switch. “And she went ‘I’ll probably listen to Greg but if he plays a bad record Mummy I might listen to you, just to see if you’re all right’.”

Ball was good to James the night before his first breakfast show. “We got to know each other quite well over our respective Sport Relief challenges,” he says. “To the point where the night before my first day on breakfast we had a really lovely phone chat where she calmed me down and wished me so much luck and said Nelly will be listening, you’ll be great and then Nell screamed ‘good luck!’”.

James thinks she will do well. “She’s an incredibly warm personality, and that’s something you really can’t manufacture, you can’t fake that on the radio. There’s a lot of people that can fake warmth on TV, but on the radio you’re just so exposed, listeners can call you out on it quite quickly.”

But now they’re going to be rivals? “I think there’s a nice comedy rivalry between Radios 1 and 2,” he says. “ I see Radio 2 as a slightly fusty older relative who still listens to lots of Tears For Fears, that’s what we like to paint it as.” Though under Ball it might be less fusty, less uncle-y.

Ball’s life has been one of massive highs and lows. Born in Blackpool, she grew up in Buckinghamshire, her dad is Johnny “Think of a Number” Ball, a TV personality in the 1970s and 1980s, who told Radio 4 listeners this week how proud he was of his girl. Her early TV presenting jobs included Channel 4’s The Big Breakfast and the BBC1 Saturday morning TV show Live and Kicking, which is where a young James first became aware of her. “It was really one of the first shows that I watched and thought wouldn’t it be fun to work on TV one day and from there I discovered radio and that was really my way into this stuff,” he says.

Ball didn’t just arrive at Radio 1 in 1997 as the first female host of the breakfast show. She burst through the door, surfing in on a euphoric wave of 90s culture – Britpop and New Labour, optimism and ladettism, and all the excesses that went with it. If one picture captures that time it’s one of her wearing a cowboy hat, with a fag and a bottle of Jack Daniels, stumbling towards her own wedding ceremony, with Norman Cook, aka Fatboy Slim.

Ball encapsulated that time, but not just because of the excess and wheyhey Cool Britannia; but also more interestingly and creatively, thinks Richard Benson, a writer who was editor of The Face in the late 90s.

“Zoe represented that phenomenon in the 90s when you’ve got that blurring of what used to be called underground culture and mainstream culture,” he says. “From indie rock to superclubs to fashion going a bit high street, there was this thing where mainstream suddenly had access to alternative culture. A lot of creativity came from fusing things that had been separate before. It’s people who knew how to negotiate those hybrids who did well out of the 90s. She was very good because she had that openness to bring people together around her and make them feel at ease.”

But Ball was also caning it, going on air drunk or hungover, and her bosses were worried about her. She quit, disappeared, had a family, left Cook briefly for another DJ, came back, went to rehab, went on Strictly Come Dancing, began to present its sister show It Takes Two, which she still does and hopes to continue.

Marriage to Cook ended in 2016. Ball began a relationship with Billy Yates, a BBC cameraman. She had a Saturday afternoon slot on Radio 2, a new house in the country, things were good, and calm. Then in May last year, after a long struggle with depression, Yates killed himself. Ball cycled from Blackpool to Brighton, meeting other victims of suicide and depression, raising awareness. She made a touching documentary about it called Hardest Road Home.

As for her, there were lapses, but this summer she wrote on Instagram thanking her rehab centre. “Two years no booze – through two of the toughest years of my life. I’m not sure I’d have survived intact had it not been for my sobriety.”

Now, in January, comes another new – and very early – start: waking up with 9 million or so people, but with a clear head. “Zoe will bring her natural effervescence and energy to help set up the audience for their day,” says Lewis Carnie, boss of Radio 2. While he is proud that the Radio 2 breakfast show will be hosted by women 52 weeks a year (Sara Cox will do it for the 10 weeks Zoe takes leave), “the most important thing was to get the right person for the job, which we have done”.

Ball is not going to be paid the same as her male predecessor, Evans, who got £1.6m a year from the BBC and is now off to Virgin. Her salary will be made public in the annual BBC pay disclosures next year, but she has said she was happy with it.

On air, she told Evans she was “a crazy mix of elation, wanting to burst into tears, thinking of running away, everything, but mainly thrilled”. Even if her daughter won’t be listening. Unless James plays a bad record on the other side.

‘I can’t really remember. It was the 1990s’

Born 23 November 1970

Age 47

Career TV jobs include The Big Breakfast, Live and Kicking, Top of the Pops, and more recently Strictly Come Dancing and It Takes Two. She has hosted shows on BBC Radio 1 and 2.

High point Becoming the first woman to host the Radio 1 breakfast show in 1997

Low point The death of her partner Billy Yates, who took his own life in May 2017

What she says “I can’t really remember. It was the 1990.”

What they say “It’s just her career and it’s wonderful. When I listen to the radio, it’s Radio 4.” Johnny Ball, father, 2018