Gail Porter is having a bad hair day. To most of us, that means a few strands out of place and the odd split end. To her, it's a crazed patchwork of stubble, falling out in clumps. Her scalp is a barometer of her mental health: when she is stressed, she moults like a cat. A bad hair day is an omen.
Her hands are shaking, the combined effect of a double espresso and sleep deprivation. "It's falling out again," she says. "This morning I had to shave it because it looked ridiculous, patchy like a map of Europe. I get about two hours' sleep a night at the moment. I wake up before three everyday – it drives me crazy." She punctuates the end of sentences with: "It's all right," as if trying to reassure me.
I'm not the only one who is concerned. Her phone rings almost constantly during our chat: her friends looking out for her. I can understand why she elicits this response: she has a vulnerability that makes me feel protective (her pint-sized physique and youthful looks only add to this).
In some ways she seems improbably resilient, determined to exorcise her own demons. Instead of trying to pretend that being sectioned under the Mental Health Act in April last year didn't happen, she's writing a book about it. "It was absolutely terrifying, I didn't know what was going on," she says, adding that she doesn't think she helped herself by attacking the police officers who were carting her off.
Her time in hospital was no less scary. "We didn't have any therapy, we just sat there," she says. "People were crying and acting quite strangely, obviously. I was drugged up to my eyeballs and found it all very distressing." They kept her under observation as an in-patient at the Grove Clinic in London after she sent her then-boyfriend, the guitarist Jonny Davies, a text saying she felt suicidal. "He panicked. I was being really weird on the phone, and I think I then switched my phone off." The couple stayed together through the ordeal and Porter's rehabilitation, but split up last Christmas.
When she's not writing, Porter, now 41, puts her Scottish burr to work on voiceovers. She works in the Mary Portas charity shop for Save the Children in Primrose Hill, north London, once a week. "I take loads of my stuff in," she says. "And I end up buying more things than I get rid of."
She also helps the Little Princess Trust, providing support for children with hair loss. Porter her self started suffering from alopecia in 2005, after post-natal depression and the separation from her husband, the Toploader guitarist Dan Hipgrave. "I'm quite happy about not wearing a wig," she says. She supports children going through chemotherapy or with alopecia. "I went to see one girl when she was having a ballet class, and I said to her when she finished, 'you and me have something in common: do you know what it is?' And she replied, 'No way, you've just got a new camera too?'"
As with the book, instead of wallowing, she uses humour to distract herself. Incredibly, she puts her humour at the mercy of audiences, doing stand-up at the Comedy Store in London. "It's quite hard – I physically threw up the first time I did it – but I enjoy it," she says. When not on stage, she says she tries to make people laugh so they have no chance to talk about anything serious.
And so even while she appears to be up, she is down: the gulf between perception and reality never wider, ironically, than when she was most successful. In the Nineties she was ubiquitous, hosting Top of the Pops, The Big Breakfast and Live & Kicking, a fixture in lads' mags; one of the faces of ladette culture.
Her body was projected – 60ft tall and naked – on to the Palace of Westminster in 1999 to promote FHM magazine's 100 sexiest women poll. She knew nothing about the stunt and had some awkward explaining to do to her family. "My dad still never discusses it. I phoned my grandpa right away. I was like: 'Grandpa, my arse is on Big Ben – I thought I would warn you'. He was fine; he said he'd fought in the war and it didn't bother him."
I'd imagined the so-called ladettes of that era – Porter, Zoe Ball and Sara Cox – as friends. "All us girls all going out together? No, it never happened. I don't even know Zoe, though I met her dad once. It's so bizarre: even I was thinking it sounds like we were having the best time."
In private, she was closer to the bottom. The good-time party girl was hiding the symptoms of depression, which started when she was 19. "It got worse the older I got. And as more things happened: my mum dying, my grandparents dying; my dog dying, my friend committing suicide, one thing after another. I can't cope with things like that."
Her mother had lung cancer, and died in 2009, aged 60. "The doctors thought she had asthma; they kept giving her inhalers," she remembers. "She's stoic and Scottish and didn't like to bother anyone. It was really tough – I still find it hard." After she was diagnosed, Porter would visit her mother while she went through chemotherapy. "This elderly nurse tried to put me to bed; asked where my ward was, because of my hair. I was like: 'She's the sick one, I'm just bald!'" She describes herself as crazy a couple of times while we're chatting in her local café in Belsize Park, north London, but many people would empathise with her inability to calm her whirring mind.
Despite this turmoil, she comes across as sensitive, likeable – and incredibly concerned about those around her. "Mum's a worrier, she looked after everybody apart from herself– I think it runs in the family," she says. Porter checks daily on two elderly ladies in her neighbourhood, making sure they are all right.
Less encouragingly, she has recently come off her anti-depression tablets, without discussing the decision with a doctor. "I'm just waiting to see what happens next," she says. She hopes to return to the Cabin in Chiang Mai, northern Thailand, a rehabilitation centre she visited last year. "They did mind-mapping, where you write down what you want to achieve, where you are going wrong – and how you managed to fuck everything up," she says. "It was the first time I felt calm in years. I slept there. Every night. Proper sleep."
Travelling on an underground train, we chat about alcohol. Far from being a ladette, Porter doesn't keep alcohol in the house. There is reason to hope she can keep angst at arm's length: her face lights up when she talks about her daughter, Honey, now nine, from her marriage to Hipgrave. "She's playing Henry VIII in the school play. She's great fun – and very grown up," she says.
She shares care with her ex-husband, though Honey stays with Hipgrave when Porter is ill. "She knows mummy has bad days and not the best days. So I do worry," she says, "because I feel really guilty about the way I am."
1971 Born in Edinburgh, to parents who run a construction business. She studies at Portobello High School.
1994 Graduates from West Herts College with an HND in media production, before working as a runner and a children's television presenter.
1997 Presenter of ITV's Fully Booked.
1999 FHM projects a 60ft naked image of her on to the Houses of Parliament to promote their poll of the world's 100 sexiest women. Begins hosting Top of the Pops.
2001 Marries Dan Hipgrave, the guitarist with alternative rock band Toploader. Porter cancels her honeymoon to work on a show for BBC2.
2002 Daughter Honey is born.
2004 Porter, who has already suffered post-natal depression, struggles with depression after her marriage to Hipgrave breaks down.
2005 Starts suffering from alopecia, after being diagnosed with bipolar disorder and attempting suicide. Becomes an ambassador for the Little Princess Trust to raise awareness of hair loss.
2011 Sectioned under the Mental Health Act, after a breakdown. Splits from boyfriend Jonny Davies at the end of the year.
2012 Writes book about being sectioned, and is in talks with BBC3 about a mental health season. Does voiceovers for Nickelodeon and voluntary work for Save the Children.