In case anybody doesn't know it, a dramatic change to London's skyline is emerging in the shape of the Shard, a skyscraper on the city's South Bank that resembles a giant wigwam of glass. When completed in 2012, it will be Europe's tallest building. And Irvine Sellar is the man responsible for it.
A visit to the developer's office in west London leaves you in no doubt that this building is on a scale that the capital has never seen before.
Artists' impressions showing how the tower will dominate the capital adorn most of the walls. It is impossible to miss the scale models and brochures scattered across his über-modern and trendy headquarters. As if to press home the point, even the receptionists he employs are taller than average.
Mr Sellar is undoubtedly proud of the project. Building work started last year, and he promises it will be built in time for the start of the London Olympics, when the eyes of six billion people will be on London. There are now 22 floors of the concrete core, which is already peaking above some the buildings around it. And it is still only about a quarter of its eventual height.
The tower will stand 306m (1,004ft) tall, with 1.361 million sq ft of floor space – 600,000 for offices and 65,000 for flats. A hotel, already snapped up by Shangri-La group, will take up 200,000 sq ft, with the balance set aside for restaurants, shops and viewing galleries. It will have 44 lifts, which Mr Sellar calls his "champagne bubbles".
The whole project, known as London Bridge Quarter, will also include redeveloped London Bridge rail and bus stations, and other buildings. The whole thing will be ready in 2014.
In the 10 years since he first unveiled the plans, Mr Sellar has faced down a number of opponents. Most, understandably perhaps, object to the sheer height, and it is impossible to argue that the Shard will do anything other than rule over the London skyline.
"We got planning permission at the end of 2003, but there have been many times when we have thought, 'what's Plan B?' We have always had problems: Southwark council was not happy at first because, due to not the best timing in the world, we submitted our plans when 9/11 was still in the memory of everybody so, of course, the planning committee were very concerned about a tall building being a target."
During the public inquiry, the Shard also faced opposition from a combination of groups, from the Royal Parks Foundation and English Heritage, to St Paul's, which argued that the building would cast a metaphoric shadow over the cathedral designed by Sir Christopher Wren. St Paul's was itself London's tallest building when it was completed in 1711, a title it held until 1962.
Renzo Piano, the Italian architect who designed the Shard, was asked during the month-long public hearing if the skyscraper would detract from St Paul's. "When together, the two buildings will kiss each other," he replied. According to Mr Sellar, his architect later conceded privately that he doesn't rate the design of London's iconic cathedral.
As well as having a silver-tongued architect, Mr Sellar has also been lucky with the funding for the project. In the autumn of 2007, one of the original backers of the project, the Halabi family trust, sold its stake, threatening the future of the tower. By the start of 2008, however, a consortium of Qatari investors had paid £150m to secure an 80 per cent stake and take control.
Mr Sellar says he has a good relationship with his Middle Eastern investors, even though his own stake in the project was cut to 20 per cent. The private Qatari investors have now transferred their interests in the project to their government in Doha.
Despite the obvious fact that it won't be, Mr Sellar, borrowing a phrase from the capital's former mayor Ken Livingstone, says that the Shard will "be owned by Londoners". The public will be able to "go into the building and view the building. You can eat there, and sleep there because of the hotel. It is the first vertical town, and how many buildings can you say that about?" he adds.
This stands in contrast to some of the other ambitious plans for new towers in the City of London, he says: "The 'Cheese Grater': it's an office building, the 'Walkie Talkie': it's an office building. OK, they may have a terrace, or a restaurant or something, but they are not buildings Londoners feel that they can own. I'm sure it will become a terrific tourist attraction in time."
The other projects, planned by the publicly listed Reits, British Land and Land Securities respectively, were, in effect, mothballed after the financial crisis. So far, neither company has reported any progress.
The Shard is a long way from where Mr Sellar started his business career in the 1960s. Like a number of East Enders with little formal education, Mr Sellar started by selling clothes on the market stalls around London and Essex. That took him to the then thriving Carnaby Street, which, "I hit at just the time," he says.
After a period on Carnaby Street, he moved into the big time and founded the first of his Mates by Irvine Sellar stores, becoming, he claims, the first retailer to sell men's and women's clothes in the same shop. "I think the successor to what we did is Next, which is a similar thing. I was in every known high street, and well known in Scotland, England and Wales during the 1970s. And it was a very professional business: we had 3,000 employees and stores all over the place. I don't think there was a person in this country that wasn't wearing something from us. Mates by Irvine Sellar was a much bigger brand than any I've known since."
The move to property came when he realised he needed fewer staff and could make more money by dealing in buildings, rather than clothes. He does admit some regret at not sticking it out in retail, but the Shard, and an appearance, in 346th place, on the Sunday Times Rich List with a fortune of more than £150m shows that the move was not without its benefits.
He counts Prince Andrew as a friend, who he says has been influential in helping the Shard project. The Prince has long held a special interest, says Mr Sellar, without elaborating. Perhaps because of his reputation for attacking a number of modern architectural projects, Andrew's brother, Prince Charles, has given the Shard less attention, "which is a plus", he says.
Not everything has gone according to plan as a property mogul. In 1991, his first property business, a retail specialist called FSM, went into administration. Within 12 months, he was back, with another developer with more of a focus on industrial sites, eventually leading to the Shard.
Many would argue that his biggest task, to fill the Shard with tenants, is still to come. Even though Transport for London is the only confirmed client so far, Mr Sellar claims to have no concerns, even though an empty Shard would be seized upon by those who have argued that it is an over-ambitious plan: "It is the standout project in London," he says. "We're not marketing it yet, and that's deliberate. We won't start until the end of the year, or the beginning of next, when the building will be very visible. And then the market will come to us."
Concrete jungle: London's other tower projects
The Shard might be on schedule to be completed in time for the London 2012 Olympics, but a number of its rivals to the crown of London's most ambitious building project are struggling to keep up.
The financial crisis has delayed Land Securities' so-called "Walkie Talkie" development in Fenchurch Street. The office block is still on hold as the developer looks for partners to spread the cost of the project, as part of its "de-risking" strategy. The group say it has been talking to construction companies about costs.
British Land's "Cheese Grater" also shows few signs of life after falling victim to the credit crunch. The company confirmed yesterday that there was no update on the planned Leadenhall Street tower. The group said greater demand for office space could revive the project, however.
Progress remains slow on the two-tower Heron Quays West project, the planned 156m (512ft) tower being developed by Canary Wharf Group in Docklands. The development was approved by the London Borough of Tower Hamlets two years ago but there has been little movement since then. A spokesman for the group yesterday confirmed there were no plans to start building and no potential tenants had been found.
The Heron Tower in Bishopsgate is in much better shape. The 242m (794ft) tower will open its doors in March next year and, until the Shard is finished, it will be London's tallest building. "Heron International believes the timing of the development will be very good, as it is one of very few prime office developments scheduled to be completed in the City over the next few years," a spokesman said.
Work is moving on gradually at the site of the "Helter Skelter", with building on levels above the basement due to start in May. Arab Investments, the 288m (945ft) tower's developer, has reportedly had pledges of more than £550m of debt financing to allow it to continue construction on the project. Khalid Affara, the managing director of Arab Investments, said: "We have been in discussion with a variety of banks about funding the development of the scheme and these have been very positive."