Street-Porter has cultivated the image of a woman apart - earlier in Travels with Pevsner, she confides that she prefers to wander the tourist centre of Scarborough on wet and windy days. In appearance, accent and achievements, she's a one-off. Whether ranting at staff about failing equipment on Nightmare at Canary Wharf, the chronicle of her year in charge at L!ve TV, or matching Ffyona Campbell barb for barb on a BBC2 documentary, she is a unique presence.
It hasn't always won her friends, but it has made her famous. Helped in the early days by wicked Kenny Everett spoofs, she is now one of the most high-profile women in television. People could probably name her before any of the grey executive suits who contributed to her leaving the BBC in 1994. There, she held the influential posts of Commissioning Editor for Youth Programmes and Head of Independent Commissioning for Entertainment, but was always denied the job she most craved - the controllership of BBC2. Not for nothing did she launch her now-notorious attack on the M-people - "male, middle-class, middle-aged, mediocre" - at the Edinburgh Festival in 1995.
She elaborates on the male conspiracy theory in A Night in with the Girls, a BBC documentary charting the history of women in TV, to be broadcast next week. "The reason I left the BBC was because I didn't think I was going anywhere," she explains. "Why are there now more men running the BBC than there were when I left? John Birt said half the BBC's staff was going to be female by the year 2000. He may have meant it, but other people are not executing it. You can't tell me it wouldn't be possible to have a woman running BBC2. If you're a woman, to get on you have to have a sense of humour that men don't need to have. They just have that funny `men' way of talking to each other - although a lot of them still seem to have problems communicating."
Perhaps unsurprisingly, having left L!ve TV in 1995 after alleged clashes with executives there, Street- Porter says she is "not rushing back to being a TV executive. I like doing more creative things now. I can't see the point to the TV executive existence anymore. I did it for nine years, and at the end, you're not thanked. You're completely replaceable, a cog."
To her eclectic CV - TV exec, chat-show host, film producer, President of the Ramblers' Association - can now be added "architectural presenter". She brings to this task what she brings to everything - immense enthusiasm. "I wanted to make a programme that was fun and showed architecture as something living, not dead," she declares. "There are a lot of architecture programmes that blind you with the history of buildings. When I was at the BBC, I was in violent disagreement with the bended-knee position. Buildings reflect the spirit of the age and people's madness. Having built my own house, I know you have to be mad to do it. With this series, I've tried to celebrate the folly of it."
She is certainly a persuasive presenter. "I like her directness," opines Jamie Muir, the series producer of Travels with Pevsner. "She'll always have a future as a presenter because she's wonderfully direct. She has a straightforward enjoyment of things and an approachability. After all that business with L!ve TV, it was also nice to show that other side of her, the softer, funnier side. People who know her know she is an extremely funny woman."
All this will come as a surprise to her detractors in the business, the types who are always quoted unattributably as they sink the knife between her shoulder-blades. But she should be used to abuse by now - it's trailed her ever since she made her television debut as a presenter of the London Weekend Show in 1975. A towering six-footer with prominent teeth and an even more prominent penchant for loud clothes, she has never failed to catch the eye. She also has a reputation for being difficult, which she does nothing to deny. "I don't suffer fools, and was very demanding as an executive," she admits. "I probably was difficult to work with, but so are most blokes."
It is the Estuary accent, however, that critics have most frequently latched onto. "I didn't like what the press wrote when I was on the London Weekend Show," Street-Porter remembers. "I used to cry and not want to go to work. I was so under the microscope, it terrified me. Every show I did was endlessly dissected. I wanted to say to them, `It's only TV'."
She soon came to see that the power lay in the producer's throne. "I realised you've got to go through the production side and be an executive to run it," she recounts. "When you're on a show, you're a puppet reading out other people's words."
Street-Porter is nobody's puppet anymore. She has put in a proposal for a BBC series about walking, she has an option on a novel called The Priest which she hopes to turn into a film, and she is working on her own novel about the TV industry which she promises will be "shock-horror revelation".
Her great skill is as an ideas person. "I get them from all over the place," she says. "I can't bear to be in. I go to a lot of different things because I like to understand what the mood of the moment is. People might say my ideas are trivial, but it's hard to be trivial, it's an artform."
As she reaches grande dame status, Street-Porter is now able to laugh about the way perceptions of her have changed over the years: "When you're over 40, you're considered a voice of women. Now I'm an icon to the Spice Girls. Before, I was a common tart."
Janet Street-Porter appears on `A Night in with the Girls' on 16 and 23 Mar, and presents `Travels with Pevsner' 22 Mar
1946: Born in London, the daughter of an electrician and a dinner lady. Brought up in house in Parsons Green, London with outside lavatory
1950-60s: Went to grammar school where she got 11 O-Levels and four A-Levels. Studied architecture at Architectural Association School
Late 1960s and early 1970s: Worked as a journalist on Petticoat and the Evening Standard. Married photographer Tim Street-Porter, the first of three husbands
1975: Invited by John Birt to become a presenter of the London Weekend Show
Late 1970s and early 1980s: Fronted Saturday Night People, Around Midnight, The Six O'Clock Show and The Chat Show
Mid-1980s: Created Network 7 for Channel 4, which won a Bafta for originality. It also helped gain her the "yoof" tag, which, much to her irritation, has stuck
Late 1980s and early 1990s: Commissioning Editor for Youth Programmes and Head of Independent Commissioning for Entertainment at the BBC. Also, made President of the Ramblers' Association
1994-95: Managing director of new cable station, L!ve TVReuse content