Roger Madelin has waited 20 years to tackle the father, mother and great aunt of all regeneration projects: London King’s Cross. So how come he’s looking so calm, so relaxed?

Roger Madelin tells you cheerfully that he sleeps soundly. You have to be impressed. The trials and tribulations of delivering central London’s biggest regeneration project for a century and a half would have lesser mortals than the Argent chief executive counting endless flocks of sheep.

First there’s the planning permission. Madelin could be starting 2006 with the best possible news, or the worst, as in January Argent’s King’s Cross Central will come before Camden council’s planning committee. The omens are good for the scheme, which has been more than six years in the making, but as every developer knows, the system is fickle. “We’re cautiously optimistic,” says Madelin, “but if they do refuse we’ve got 67 acres that is not going away.”

The second possible cause of insomnia is the sheer size and scale of the project. As Madelin acknowledges, London regeneration projects of this scale and vision, from the Adelphi to Canary Wharf, have had a reputation for sapping the lifeblood of their parents. But – leaning back in his chair and running his hands over his closely cropped head – the straight-talking Madelin shows little sign of anxiety. “Because the project is so huge we have to follow on big, and the risk is high,” he says. “We’ve got to be brave – and we’ve got a good track record in doing risky things.”

On the wall of the meeting room at Argent’s West End office hangs a picture that serves as a powerful reminder of what this project is all about. It shows King’s Cross’ great skeletal Victorian gasholders, symbols of industrial heritage and subsequent decline, framed against a blue sky. “It was a very mysterious place,” Madelin says of his first impressions of the site. “It was extraordinary to find that kind of Victorian microcosm. It felt dangerous even in daylight. It was edgy.”

Argent aims to retain the heritage of the site but to sweep away the less desirable aspects of King’s Cross’ past. The linked triplet of gasholder frames, now held in storage, are among the million square feet of heritage structures on the site that will be retained, given a healthy dose of TLC, and put to new uses. Alongside the existing structures, Argent will develop about 60 buildings – offices, shops, homes and all the other essentials of life.

When Madelin first set eyes on the site in the 1980s, it was, he says, “totally out of our reach in every way possible”. By 1999, with Birmingham’s Brindleyplace under its belt, Argent was better placed to bid. “I told the landowners, LCR and Excel to save their time and choose us,” he says.

Brindleyplace might be the scheme that made Argent’s name, but King’s Cross Central is in a different league. Brindleyplace was a mere 17 acres and was predominantly an office scheme. “Because of its scale and diversity, the opportunity of King’s Cross is extraordinary,” says Madelin. “Making sure that we get the right mix will be the difference between a fantastic success and something that is okay.”

It was all this that attracted Madelin to the project. “All developers want to do something that they can be proud of,” he says. But Argent’s pride stops well short of hubris, as Madelin explains: “It’s nice producing nice buildings that are nice places to be. But at the end of the day buildings aren’t that permanent, and it’s the streets and spaces that will be there for hundreds of years.

The scheme isn’t ours, it’s London’s. There will be 20 new London streets and 10 new open spaces.”

After consultation with stakeholders Argent has also added more ingredients requested by local people, such as two primary schools, a health centre and more homes. The area will get 1946 units, one-third of which are destined to be family homes, rather than small apartments for transient renters.

In order to create all this Argent will be commissioning work from up to 50 architects. It won’t be going for architectural icons. The buildings will include some gems, but Madelin stresses that King’s Cross Central will not be “an ego-contest for architects”. Which is not to say that he lacks grand ambition. Madelin says his objective is to make King’s Cross Central “the most exciting piece of city in Europe”.

The first phase of development at King’s Cross, worth £350m, will include £85m of infrastructure works as well as buildings, but the scheme as a whole won’t only be about physical regeneration. Argent will be tapping into surrounding cultures, communities. At present he is musing on string quartets or a demonstration of photovoltaics. Such genteel pursuits are a far cry from the drug dealing and prostitution that have characterised the area. Local people have told Argent they simply want the place to be safe and clean. Madelin is aiming higher: “I want people to wake up on a sunny day and know without looking in Time Out that they’ll find something stunning there.”