On one wall there is a poster for one of her more celebrated commissions, Rolf on Art - a programme that critics saw as clear evidence of the dumbing down of BBC arts coverage, but which she insists was a clever way of opening up the visual arts to mass audiences.
Not far off along the wall are pictures of the living "idents" for BBC One that separated her programmes - such things as the mountaintop t'ai chi performers and wheelchair dancers that marked her reign as controller. She had wanted a more dynamic image for the flagship channel than the travelling hot air balloon she inherited. Now her successor at BBC One, Peter Fincham, former chief executive of talkbackThames, is talking about a new image, and the wheelchair performers could soon be no more.
Naturally, on the walls there is also a montage of talkbackThames productions that range from The X Factor, The Bill and The Apprentice to Grand Designs, Never Mind The Buzzcocks and They Think It's All Over.
But one framed exhibit is by far the most interesting. It is devoted to the classy television drama by Stephen Poliakoff The Lost Prince. Heggessey commissioned the production when she was controller of BBC One, and Fincham and talkbackThames delivered the high-end hit to her.
"There, you see. Talkback and BBC One - perfect synergy," says Heggessey with a laugh, in her first interview since moving back to the independent sector four months ago, after a 12-year stint at the BBC.
The effects of the most dramatic job swap in recent British broadcasting history are still continuing, courtesy, once again, of Stephen Poliakoff.
Heggessey, the BBC One controller, commissioned two new Poliakoff films from Fincham of Talkback. Now it is Heggessey of Talkback who must deliver Friends And Crocodiles and Gideon's Daughter to Fincham of the BBC for broadcast next year.
"They are pretty much finished and they are fantastic," insists Heggessey with the even greater enthusiasm of a programme-seller.
Isn't it weird suddenly having to pitch ideas at someone who not so long ago was pitching pretty similar ideas to you?
"Funnily enough, I don't find it weird at all. This is my job now and I have just stepped into the role. I am a natural kind of salesperson. I am a pitcher and even running BBC One, you are constantly pitching the channel," she explains.
Now she can unselfconsciously pick up the phone to the ITV director of programmes, Nigel Pickard, and say how delighted she is that The X Factor is knocking spots off BBC One on Saturday evenings.
Obviously Heggessey has long since made the mental switch and is effortlessly talking about "we", as in talkbackThames, and "they", as in the BBC, whose controllers and commissioners now have the frustrating power to reject her ideas.
One of the best questions she has been asked in recent weeks was whether it was Heggessey or Fincham who got the best deal out of the job swap.
"We both got a fantastic deal because we have both got something completely different to what we had," goes her reply.
A cynic would suggest that Fincham had made his millions in the independent sector and can now afford the luxury of a BBC salary. Heggessey, after establishing her management credentials at the BBC, was off to double her salary at one of the top three independent productions houses in the UK, ultimately owned by RTL, Europe's largest commercial broadcaster, which is in turn controlled by international media giant Bertelsmann.
"Obviously it's good to get to a stage where you feel you can capitalise on your experience and you can start to make a bit of money. But money is not my main motivating factor. Happiness in my job and whether the job challenges and stimulates me is the main thing," she says.
She adds that she is the main breadwinner in her home ,while her husband, Ron de Jong, a musician and composer, provides "an anchor and security" for their two girls.
To get to talk to Heggessey in her inner sanctum at the headquarters of talkbackThames, off Oxford Street, is an unusually interesting architectural journey compared with the claustrophobic corridors of the BBC. The headquarters of a company with a turnover of £140m a year seems to be little more than a shop front without a door, with only the company name on display in the window. The real entrance is down an alley at the side and then, behind a series of heavy wooden doors, the building, which won an award from the Royal Institute of British Architects in 2002, opens out. Tiers of redbrick offices look out on an extensive inner courtyard with lots of open thinking space and gardens in different layers.
"A lot of people do work outside. It's a very positive and free work environment," she says. It's a bit like the Tardis on one of Heggessey's last big BBC hits - Dr Who.
But was there an element of choreography in the job swap involving the BBC controller who also commissioned Strictly Come Dancing?
"It wasn't planned. Nothing about my career has ever been planned, and I would have happily done another year or even two at BBC One, a job I absolutely loved," says Heggessey.
The BBC executive had started to think about what should come next. After a stint of nearly five years, she was already the longest-serving BBC One controller since the 1960s and the pressure is relentless. She decided her dream job would be to run a large independent production company. The chances were slim, because they are usually run by their founders, and she had no intention of starting again at the bottom. It was too slow, and anyway, she had got too used to running things.
And then the call came from an intermediary. "When I heard what the job was I thought: 'If I wait another year or two, that job is not going to be there nor another job like it.' It was a case of seizing the moment," says Heggessey.
In turn, during meetings to brief her on her new job at talkbackThames, she helped to persuade Peter Fincham to become a late, dark horse entrant in the contest to find her successor at the BBC.
During the conversations, Fincham began to realise how much fun Heggessey had had at the BBC, but he still protested that he had his life plan. The aim was to take at least six months off, write a book and then decide what to do next.
"I just said to him life plans are meant to be changed," recalls Heggessey who believes that her decision to move from a top job at one of the UK's most distinguished broadcasting organisations is a recognition of the growing maturity of the sector. Until recently, such things simply didn't happen.
Not only did she help persuade Fincham to apply - she probably wasn't alone - she also discussed it informally with her friend Jana Bennett, the BBC director of television.
"Jana was also very interested in him [Fincham]," says Heggessey.
Four months after arriving in Newman Street, Heggessey says she absolutely loves her job swap. Despite being a "super indie" with 400 permanent staff and a further 400 on the roster at any one time, talkbackThames is still small compared with organisations such as the BBC. The total cost of everything that appears on BBC One is around £1bn a year, and in a previous job at BBC Production, Heggessey was responsible for about 3,000 staff.
But at the BBC her time was hardly ever her own, with a merry-go-round of set pieces and pre-scheduled routine meetings and a need to reference everything up and sideways. At talkbackThames she is largely left to her own devices, apart from a monthly board meeting with her immediate boss, Tony Cohen, of RTL subsidiary Fremantle.
"Now I can do a lot of my day job during the day, as opposed to the BBC where I would often take it all home with me," she says. At talkbackThames she has the freedom to create her own structure and plans to concentrate on being "a creative leader" for her staff.
"I see my role as being a catalyst to make things happen, to be a bridge between the programme-makers here and the broadcasters," says Heggessey who believes that the past five years spent thinking about audiences will help talkbackThames producers come up with programmes that need to be made and that commissioning editors will want to buy. At the BBC she also got extensive experience of providing content for multimedia outlets, including mobile phones.
In a meeting with her staff last week, she began to set out her priorities for the indie's future.
"We really under-exploit our expertise in both drama and entertainment. We are fabulous entertainment producers. The X Factor and Pop Idol are executed in a fantastic way, but these are just two titles and we need to invest massively now in development in entertainment, so that we can start to come up with original ideas and produce more shows," she says.
She believes both the BBC and ITV will be willing buyers and that there is a real opportunity to become a supplier of volume drama to the BBC.
Talkback, in the past, focused on BBC Two and Channel 4, while Thames had its main relationships with ITV. Apart from They Think It's All Over and dramas such as The Lost Prince, the company made little for BBC One. All that could change as a result of the job swap.
Talkback and Thames had already been brought together as a business entity, but Heggessey wants to deepen the relationship between the various parts and plans to bring people, split across four different sites in London and Buckinghamshire, together more often. There will be more cross-company events and joint brainstorming sessions. "I am a great believer that when you get creative people colliding together, then great things happen," she says.
There have been moments of creative collision in her own career - one of the most memorable in a television confrontation with the consumer journalist Roger Cook in the early 1990s.
Heggessey, who was then working for small independent Clark Television, in the days before super indies, made a documentary with Ken Loach on what she saw as the unfair treatment meted out to miner's leader Arthur Scargill by both Cook and the Mirror.
Cook declined to be interviewed, so Heggessey did what Cook would have done and door-stepped him over breakfast at a Birmingham hotel. When he was still unforthcoming, Heggessey, who barely makes it to five foot tall, chased the large and bulky Cook up the street, asking questions and filming as she went.
"It was a great moment and it provided great television," says Heggessey, who was at the time deputy editor of Hard News, the Channel 4 programme that cast a cool eye over the activities of the press.
Paul Woolwich, editor of Hard News and now a senior current affairs producer at the BBC, believes the threats she faced at the time from newspaper proprietors, editors and media lawyers helped to make her fearless. "I think Lorraine was exceptionally ambitious even then and with a steely determination and an enormous bundle of charm and that laugh of hers that carried her through everything," says Woolwich.
Heggessey believes that working in Jana Bennett's science department as an executive producer when she returned to the BBC was an important turning point - producing series such as The Human Body and editing QED.
"It really started to give me the understanding that if you could find the right story and the right approach, then you could tackle quite weighty subjects for mainstream audiences," she argues.
Animal Hospital, which rejuvenated the television career of Rolf Harris, was also a big hit for her.
She was about to leave the BBC for a return to the independent sector when she was asked to run BBC children's television, at a time when her daughters were aged around four and eight.
"Short of taking over Hamleys, this was the next best job for them," she says of a job that introduced her to different genres, such as entertainment and comedy, to add to her mainly news and current affairs repertoire.
She did, however, raise a few eyebrows when, after Blue Peter presenter Richard Bacon was sacked for involvement with drugs, she decided to seize the limelight and go onto the programme live to explain why to the young audience.
After a stint as deputy chief executive of BBC Production, she was invited to apply for the job of BBC One controller.
"There had been no plan or structure in my career. I have zigzagged all over the place, but suddenly all the pieces came together and gave me the experience I needed collectively to be able to run a channel like BBC One," she says.
Heggessey regards arguments that she was responsible for the dumbing down, or over-popularising, of BBC One as "such old ground" and "demonstrably unproven".
She was the first BBC controller to beat ITV in audience share but that, she explains, was largely because of the strength of the channel's daytime schedule. She attracted audiences as large as nine million to ancient history by using computer-generated images to help tell the stories of the Pyramids and Pompeii.
"I even got my maths programme on - The History of One, which Terry Jones presented," says the grammar school girl from Middlesex who studied English at Durham University.
She does concede that arts programmes did virtually disappear for a period from BBC One before the BBC governors complained and series such as Imagine and programmes such as Leonardo.
"It wasn't a deliberate policy [the missing arts programmes] but I think what happened is you can't keep your eye on every ball simultaneously and we took our eye off that ball. The focus was on entertainment," she confesses. It was also the focus of director-general Greg Dyke with whom she had a close working relationship, largely because they are similar direct characters. She has even been called "Dyke in a skirt".
Heggessey is most pleased about broadening the range of BBC One, particularly through shows such as The Natural History of Britain and making clear that a mixed channel such as BBC One "could continue to be a force to be reckoned with".
Now her focus is on helping to build up - not just talkbackThames or even the independent sector, which has seen the merger of companies and, with it, the emergence of multi-genre indies, but the entire British production sector.
Someone needs to invest more in programme development, she believes, if Britain is going to continue to compete on a global scale.
The BBC funds some pilots but "it is quite surprising to me to discover that ITV doesn't fund development to any significant degree". Heggessey accepts that the independent sector will have to come up with the development money.
"If we are going to break through to the next level, which I think is managing to get exportable drama, and there is no reason why we shouldn't be able to do that, then we need to invest more in development," she says.
Might she one day return to the BBC from the independent sector as she has done once before? She insists there is no other job at the BBC that she wants. Director of television is just not her kind of job because she prefers rolling up her sleeves and getting her hands dirty with the programmes, rather than strategy and politics.
But she won't turn down the BBC director-general's job?
"I might do. I have never planned anything and I don't see myself as a future director-general. Now that I'm here, I think I'll probably spend the rest of my career out either in the independent sector, or - who knows? - working with other broadcasters. We'll have to see. I could easily stay here 10 maybe 15 years," says the 48-year-old Heggessey.
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