It's all about taste: Redesigning the River Café

Stuart Forbes was Richard Rogers's project architect for the Millennium Dome, and he was a senior designer on Heathrow's Interminable Five building. That means he's operated at the very top of his profession. What, then, is he doing eating slivers of prosciutti di Parma and talking about the hots? The only dome in view here is the white clay bulge of a Valoriani wood-burning oven.

We are in a legendary London restaurant, the River Café on the Thames Path at Hammersmith. Stuart Forbes Associates were given the task of renovating it – a challenge complicated by a kitchen fire in April that exposed, for the first time, the potentially lethal hazards of extractor conduits that passed through properties above the restaurant. Forbes duly found himself at the pivot point of a £2m makeover, under the direct eye of Lord Rogers and the casual scrutiny of more than 100 designers at Rogers Stirk Harbour in the building next door, a crew that has always regarded the River Café as something of a staff canteen.

Rogers could have appointed any of the dozens of talented architects who have left the practice in the past three decades to go solo. Why Forbes, whose three-year-old practice has completed residential projects in London's posher enclaves, retail and commercial schemes, the Blackrock Clinic in Dublin, and the Festival Pier in London?

It's not too outlandish to suggest that it may have had something to do with Forbes's dual obsessions – rowing; and design details. He took a silver medal in the coxless fours in the 1983 world championships and a gold in the 1986 Commonwealth Games, and is still a familiar presence at Henley and the London Rowing Club.

The River Café faces the Thames, more or less opposite the Harrods Furniture Repository, a key marker-point in the Boat Race. And something about the restaurant's new look suggests the sculling equivalent of Vorsprung durch Technic: there's a super-refinement of details, surfaces, lighting and ergonomics that has turned Ruth Rogers's and Rose Gray's shrine to Italian provincial cooking from a vivacious culinary punt dating back to 1987 into what Le Corbusier would surely have described as a machine for eating in.

And what a beautifully unmean machine it is, quite unlike the cucina I first experienced not long after it opened. Having had the temerity to write in The Independent about the cost of keeping Rogers's then new Lloyd's Building clean, I was given a polite but pointless grilling in the practice's conference room. Then I was taken next door into a culinary domain – complete with the pie-faced, pre-famous Jamie Oliver – which was then unique in London.

Architecturally, that almost primal interior had great clarity in terms of spatial demarcations and detailing; but as it got bigger (the original restaurant was about half the size of its later manifestation) it became obvious that this formal physical clarity was not matched by an equal seamlessness in terms of cooking processes.

Forbes knew nothing about restaurant design when he accepted the River Café brief. Before the kitchen fire interrupted the project, he stood in chef's whites in the kitchen – "a fraud in the corner" – simply watching what happened, and assessing the relationships between various bits of cooking kit, the process of getting food to the head chef's pass, and the physical movements of everybody concerned.

He watched not just with the eye of an architect, but with the gaze of a sportsman who knew that the difference between gold and silver was down to fractional details of kit, angles of movement, and applied grunt. "The activity here is organic, and passes through different cycles," he explains. "It's about coping with levels of demand. The brief was a voyage of discovery. Every time you forced yourself through the design again, a better idea came out. It became a consultation in which we presented plans, and they thought: do we work like that? The redesign became a critique of the staff's working style."

This critical difference between, in effect, gold and silver has turned the River Café from a pure eating experience into one in which the restaurant's measured but laid-back front-of-house vibe is mirrored behind the pass-point, a thing of beauty sheathed in mineral-acrylic Corian the colour of an unripe banana, which must have cost the best part of £20,000.

"It's taken more than 10 years to find out that the linear cooking process they had wasn't right," says Forbes. "The food was always wonderful, but in the old days you left smelling like a chef's apron because this was the first of London's open-style kitchens. The last new kitchen was put in 15 years ago. Regulations are different now, so there's a balance between air in and air out."

And between ideas and details. "The education we all get at Richard Rogers's practice is partly about breaking down the details of a problem. It's the same as working with Ruth and Rose and breaking down the restaurant's problems, the caveats and break-points. I'd never built a dome before the Dome. In essence, it was the same here. That's the thing about architecture: you get thrown a curve-ball, and you have to hit it."

At the River Café, Rogers did not want the look of the restaurant ruptured: its appearance and ambience are its brand. Forbes's interventions have been subtle, and executed with a precision that has given the place vivid new graphic and surface qualities; this is high-res eating. The slanted glazing above the long service counter has a silk-screened semi-opacity; there's softly reflective glazing behind the new bar counter; the glass wall of the private dining room allows the exclusive few to watch the cooking; tiny hanging halogen downlighters accentuate the perspective of the long room, leading the eye to the one area of almost shocking calmness: the kitchen itself.

How can so few cooks working in what is still a smallish professional kitchen serve 80 diners so quietly, and without fuss? "It's an orchestration of lines of activity and communication," Forbes says. More precisely, it's about where the key kit has been placed: the oven, the grills, the hots (hobs and ovens). And it is here where his instincts about the precision of rowing – positions, interlocking radii, communal movement – must have made small but crucial differences.

"It was down to centimetres whether something was in the right position," Forbes notes. "Here are the fridges, here's the produce. Is it going to work? Everybody contributed to this process of examining what happens in the kitchen. They all come up to me now and say they can produce many more covers, with ease – without the shoving and pushing, like Jamie used to do." It's a very good thing Britain's culinary conscience never took up rowing.