Among the ducks and the geese and the pram-pushers there are three celebrities who regularly haunt Ravenscourt Park – my local green space in west London – although not regularly enough to interest stalkers or paparazzi. Firstly, there is Michael Gambon, to be seen sitting hunched outside the park café on very occasional weekend mornings.
Then there is Toby Young and young family, although there seems to have been less of him since his 'free school' opened in September. And finally there is Miranda Hart, out walking her pet dog, a shih-tzu called Peggy – Peggy's owner resolutely avoiding eye contact with anything but the ground about six inches ahead of her. Otherwise I might have stopped her and told her how much I enjoy her sitcom, Miranda.
"Mainly I just find it a bit awkward to be honest," she says, when we finally do meet up, in a local gastro-pub halfway between the park and her house, just as my next-door neighbour walks by our table as if to illustrate the point. "I know who you are, you're a comedian," he tells Hart. "You make me laugh anyway... I can't remember the programme." She takes this in good grace, and then returns to the subject of her awkwardness. "When walking the dog I just want to be in a world of my own, and you forget that somebody might point at me, or shout 'Such fun!'..."
'Such fun!' is, of course, the very apt catchphrase from Miranda, Hart's BBC2 (now BBC1) sitcom about an accident-prone singleton who works in a joke shop. While the critics traded endless permutations on the words 'slapstick', 'old-fashioned' and 'acquired taste', Miranda built up a devoted word-of-mouth audience able to appreciate her humour without tying themselves up in knots to justify their enjoyment of something seemingly so old-school and uncool.
"Seemingly," says Hart, pointedly. "People are so passionate about comedy it makes a lot of people very cross that something seemingly a bit rubbish, seemingly mainstream and un-thought out... maybe there's anger that it's so popular. They think, 'Why are people so stupid as to think that's funny?'."
In fact, Hart constantly reworks Miranda, constantly writing and editing, she says, with the vision of a viewer holding a remote control and able to switch channels at the first hint of a longueur. And if you still feel there's anything accidental about Miranda's success, then visit YouTube to see what 'overnight success' really looks like. There's a video there of a sketch, shot over 10 years ago at the 2001 Edinburgh Fringe, in which Hart and her then comedy partner, Charity Trimm, vie for the attention of a handsome male TV producer. It's an almost exact template of the competitive relationship Miranda now has with her joke shop co-worker Stevie (Sarah Hadland).
Other characters in Miranda include her old school friends, Tilly and Fanny (played by Sally Phillips and Katy Wix), Miranda's mother (Patricia Hodge), and Gary (Tom Ellis) – aka the love interest – who works in the restaurant next door. The milieu is unashamedly middle-class, another reason for some people to look down on it – although Hart claims to be unaware of such inverted snobbery.
"I've never heard that," she says. "Perhaps I was naïve, but I hadn't considered that until this very moment. I suppose my thing is to make sure it's as universal as possible. I only really think comedy's got a problem if the central character is middle-class and her values are only middle-class and then people aren't going to relate or be interested. This character is completely classless really. She happens to be from Surrey but her goals and her fears and her problems could happen to anybody. But as the producer said, 'If they don't like the show they're probably not going to like you'."
In fact the show is so personal that Hart deliberately didn't read any reviews, although she adds that: "I definitely got a sense of the hatred – my stupid fault for being on Twitter, I suppose. Mind you, I always assumed people in the industry would hate it and completely the reverse has happened. Jimmy Carr loves it, Russell Brand loves it..."
And many women love it too, one female journalist calling her character "an uproarious embodiment of women's everyday neuroses". "I suppose that's my thing about keeping it universal," says Hart. "You can play the big fool and hopefully people like you for it and then go, 'Thank God I'm not as bad as her'. Everyone wants a friend like that, don't they? They all want a friend that's worse."
A friend that catches her skirt in a taxi door, so that she ends up running down the street in her tights, perhaps, or falls into an open grave at a funeral, or one who endlessly tumbles into coat racks – is any of this stuff autobiographical? "None of it really," she says. "They'll be things like my attitudes to stuff – like I really do love a hotel room... I get excited about the kettle and the room service – but in terms of scenes they never happened to me. OK, there's two – one being called 'Sir' all the time and the other was being locked in a park. But I was locked in for five minutes and managed to scrape out. In the sitcom world you have to take your clothes off, it's in the middle of the night, your love interest walks past, etc, etc."
In my much lither, long-haired and long-ago student days, I tell Hart, I was once whistled at by a taxi driver. I'll never forget the look of horror on his face when he drove past and realised his mistake. "Welcome to my world," she replies drily.
Miranda Hart Dyke was born in Petersfield, Hampshire, in 1972 (it's her 39th birthday next week) – the daughter of a Royal Navy officer, Captain David Hart Dyke CBE, who later briefly served as aide-de-camp to the Queen. During the Falklands War, Captain Hart Dyke was the commanding officer of the HMS Coventry when it was sunk by the Argentinians, the 10-year-old Miranda's father was badly burnt while escaping the stricken ship.
"To be honest I don't think it had an effect particularly on me," she says. "I just remember coming home from school and loads of press being outside and having to go round the neighbours to get into the house. Mum very much kept it from us. Next thing I know is that 10 days later he's back. It's an amazing story but its impact on me was minimal."
She was sent to an all-girls boarding school, Downe House in Berkshire, when Clare Balding was head girl but long before Kate Middleton spent a term there. It was the Eighties, and while the alternative comedy scene exploded in the outside world, Hart spent her time watching and re-watching her videos of Morecambe and Wise, and reworking Joyce Grenfell sketches for her sister Alice (a former actor and now a full-time mother). Miranda herself was too shy to perform or even audition for school plays. "I got stuck in that Seventies era of comedy and I still don't know things like The Young Ones and all that very well," she says. "And then in my twenties I kept watching Morecambe and Wise. I always preferred that silly, light, fluffy..."
A county-level lacrosse player ("Even if I say so myself," Hart says, with a very Miranda-like mock arrogance), she was popular for being sporty, and says that "in my old age I'm a sportswoman trapped in a fat body. Mind you, the sportswoman is slowly coming out again". What is she doing? "Pilates. I'm taking it slowly..."
At school she also showed early slapstick tendencies. "I wasn't one of the cool gang," she says. "I wasn't smoking or drinking cocktails, I was throwing water balloons at the staff." She wasn't particularly academic but opted to study politics at the University of the West of England in Bristol, while harbouring an ambition to be a comedian that would remain her own secret for at least another six years.
After the all-girls school ("I'm not sure it's the healthiest thing really"), Hart found herself confronted by "a new species of people" – men. "I was quite shy until I was about 20 and there were no serious relationships," she says. "We had a big group of friends and you all ended up snogging each other – that's it."
She's single at the moment and – being six foot one herself – says that only tall men need apply. "I think it takes a particular type of woman to be with a smaller man... Sally Bercow [the wife of House of Commons Speaker John Bercow], for example," she says. "I would like to feel protected as a woman and you wouldn't feel like that with a smaller man, I suppose.
"Being tall when I was younger I was always a bit awkward. As a teenager I was very, very thin, so I was very gangly and limby, and would sweep things off the table without realising how big my wingspan was – just out of control. A lot of women write to me and say I'm six foot and exactly the same happens – that's been lovely therapy."
This awkwardness would later feed into her comedy, of course, but her comedic ambitions were still unexpressed when, after university, Hart suffered what she calls "a six-month blip", back living with her parents, and suddenly agoraphobic and with what she has described before as depression, but what she dismisses more lightly to me as "sitting around in my pants feeling a bit sorry for myself. That's an official syndrome, by the way...
"Everyone – particularly my female friends I speak to – all say 'I wouldn't be in my twenties again if I was paid. It's a difficult time. If you did go to university you're leaving that environment and suddenly you're working out what on earth your life's meant to be. But it's when I started writing, so a good thing came out of it."
First, however, there was a succession of temping jobs, including working as a PA at Comic Relief, all the while honing her comedy at Edinburgh and appearing in steadily larger TV comedy roles, from BBC2's sci-fi sitcom Hyperdrive to Nighty Night and Not Going Out. Having finally come out to her parents about her comedic ambitions, they proved supportive. "Initially they were a bit worried," she says. "They kept instilling in me how being a secretary and a PA was a very good job, but equally they never said 'Don't'. My mum said to me once years ago, which really spurred me on, 'You're the funniest person I know'. I loved that." Her mum, Diana, it should be added, is nothing like her mother in Miranda – played by Patricia Hodge with such relish ("although she's worried that people would think it was based on her").
It's been a long apprenticeship – Hart says that the first two series of Miranda took her 15 years to make – although she doesn't feel the odds were in any way stacked against her as a woman.
"There are fewer women [in comedy] but that's never bothered me because I've always known that would be the case," she says. "I've never felt like a woman fighting in a male world, I've never felt penalised. I do think there's still an inherent sexism in audiences – when a woman comes on stage in a comedy club the audience will sit up and be nervous for them and wonder what the hell's going to happen, but when a man comes on they all relax into it. And again I don't begrudge audiences that, I think, hands up, I've done that too."
Given the holy grail of TV commissioners is to find "the next French and Saunders", there is some aptness in the fact that Hart's big breakthrough came in 2008 when she was asked in to read her prototype script for Miranda at the BBC, and Jennifer Saunders happened to be in the audience – laughing uproariously. "I'd like to think it would have got commissioned anyway," says Hart. And so Radio 2's Miranda Hart's Joke Shop was born, as well as the BBC2 sitcom that took her first name as its title ("I didn't want to call it that but it was the producer's idea and I think it was the right one in terms of the nature of the show").
The next series of Miranda, which she is just about to start writing – her least favourite part of the creative process – will go out next autumn on BBC1. In the meantime, starting in January, there's Call the Midwife – a new Sunday night BBC1 drama based on Jennifer Worth's bestselling novels about a team of midwives in the East End of London in the mid-1950s. Hart plays Chummy, an upper-class viceroy's daughter who's a bit of a fish out of water. It's Hart's first straight acting role. Well, almost.
"She's clumsy and there was some stuff in the script about falling over and knocking over plate stands, and I slightly cringe because I want to step away from that. I'm sure it will take viewers quite a while to get used to it... they might be expecting me to go for a quick laugh."
Or to look at the camera, perhaps – breaking 'the fourth wall' being just one of the trademark aspects of Hart's eponymous sitcom. "I really tried to make a very old-fashioned genre contemporary, by looking into the camera, it could have song and dance moments in it if you wanted, 'You've been watching' and all that. But I was completely aware that this was most likely to die on its arse."
The opposite was the case, of course, Miranda winning converts by the week as well as multiple British Comedy Awards and Royal Television Society prizes. So is Miranda anything like Miranda? In a far less heightened way, I suppose – although accidentally spitting out some of your parsnip and apple soup could happen to anyone. And she doesn't trip into the coat rack as we're leaving the pub. She's smart, a bit shy and (obviously) funny, but not remorselessly so. She claims she's suffering from "verbal diarrhoea" because she's been ill for the best part of a month and hasn't seen anybody much, but she doesn't seem overly garrulous to me.
And just when I'd given up finding some sort of defining image of her, and am walking home, she greets me from her bicycle that has, yes, one of those wicker baskets on the front of it. It's Joyce Grenfell cycling to the village shop, which in a sense she is (this is one of those London neighbourhoods that calls itself a village, and she's heading off to the local deli). "Such fun!" I could have exclaimed, but it's such a miserably dank and chill late November afternoon that I wave back and just keep walking.
'Miranda Series Two' and 'Miranda Series One & Two' box-sets are out on DVD now. 'Call the Midwife' will be on BBC1 in January