Over the past decade he has become the nearest thing Britain has to a minister of culture, but without political office or a seat in Parliament. He has also been active behind the scenes in an increasing number of charitable ventures aimed at bringing radical change to the way in which people live in the most deprived areas and housing estates in the country.
The River Cafe (prop: Ruth Rogers, wife of Richard, and Rose Gray) is not only a de facto extension of Richard Rogers's architectural studio, and the sociable architect's natural forum, but a part representation, in delicious miniature, of the civic culture Rogers would have us all enjoy being part of.
Our single greatest social problem, says Rogers, is that we have too much leisure time. One imagines St Thomas, tackling the grilled scallops, nodding in agreement. What was once seen as a virtue - a time to stop and stare, regenerate human batteries, tend the garden - is, as far as Rogers is concerned, a vice. Why? Because, not knowing how to use free time and not having the education, training, motivation or money to do much more with it than watch television or kick a ball around, citizens feel alienated - useless, without purpose and in effect outside the system they are meant to be a part of. Or, as Aquinas had it, "a man is a slave when he does what he likes to do in his spare time and in his working time does what is required of him".
This famous Thomist aphorism has been taken up over the centuries by those - such as Eric Gill, the sculptor, letterer and essayist - who have employed it as the philosophical underpinning of utopian communities that have been dedicated to the sanctity of work. "Every man", Gill liked to say, "is a special kind of artist." St Thomas would have agreed. So does Richard Rogers.
Human beings have a need to express themselves, and this they do best when expert in some art, craft or skill, whether making wobbly pots for sale in village fayres, playing tennis, or, like Rogers, inspiring a team of architects who continue to design some of the most thoughtful and elegant modern buildings anywhere in the world.
The difference between Richard Rogers and Thomas Aquinas or Eric Gill is that whereas these earlier thinkers believed that a state of good living could only be achieved by escaping the sins of the city (Aquinas chose the monastic life, Gill a secular version of the same), Rogers believes that we can lead the good life - all of us - in the berated city.
His message seemed all the more relevant this week when I lunched with him at the River Cafe. He was just back from the Habitat 2 conference in Istanbul, where he spoke on the nature of the sustainable city of the future. Delegates to the conference were agreed that not only are the world's major cities likely to expand at an inexorable rate into the foreseeable future, but that this is not necessarily a bad thing, at least in the minds of those countless millions who are moving from fields to shanty towns. What these migrants seek is not only an improved chance of making a living, but ultimately of giving their children a chance to benefit from the riches and culture that to date only cities seem able to provide.
Our own tiredness with the city in Britain, Rogers believes, derives from the fact that we have exploited it for short-term financial gain rather than nurturing it so that it works for us not just as a marketplace, but as a place of delight and culture.
"Culture's a sticking point in Britain," says Rogers. "This week we held another in the series of public debates on London in the 21st century, at Central Hall, Westminster. The theme was culture in the capital, by which I mean the way a city lives and works, and not specifically the fine arts. People are scared of the word; it sounds grand and removed from everyday life. But unless we get the culture of the city - London, Istanbul, Bombay - into some sort of sustainable, desirable and forward- looking balance, we are condemning citizens to lead a fruitless and alienating life."
The big problem in western cities, as Rogers sees it, is that there are more people seeking fewer jobs. "Children are growing up now who are likely never to have a full-time job. If you leave them to waste their days watching TV and without purpose and money, they are at best going to be pretty much dysfunctional citizens, and at worst are going to turn to crime.
"This is happening. And what's our response? To increase policing and security, to build more prisons, to deal out longer custodial sentences.
"This is unrealistic, an expensive nonsense. Why waste money on more police and more prisons when what we should be doing is creating a viable and attractive urban culture that positively encourages people to want to join in, to do something useful, to become, in Tony Blair's word, stakeholders in civic society?"
"We also need to capitalise on the time and energy freed by the reduction in conventional employment and the lowering of the age of retirement", says Rogers. "At the moment, we view the hours between waking and sleeping that people do not spend working as redundant. What we need to build up is the notion of creative leisure. As a society, we need capital generated by the market, capital generated by government and, now, a third category, social capital.
"Social capital includes any number of different forms of voluntary and community work. We need active citizens to renew run-down housing estates and urban parks, to run community services, to create their own art, music and meeting places. Over the past 15 years, central government has increasingly taken power into its own hands and rolled the frontiers of the state over local interests and local democracy. We have to give a voice and power back to citizens at a grassroots level.
"Where would the money come from to fund new forms of community employment? Not out of thin air, I can assure you. The money we could be spending on what I've called creative leisure is currently being spent on, for example, unemployment benefit. To me this is a topsy-turvy way of going about things. Why pay people to hang around all day watching TV when they could be setting up social enterprises that ultimately would pay back to the community a value way and above the initial capital outlay?
"As people began to work in creative ways, we would see a gradual decline not only in crime - and so need less in the way of security and fewer prisons - but also of poor health. Active and engaged citizens are far less likely to be ill than those pushed to the margin of civic society. So, we'd save money on policing and health care that could then be assigned to new forms of employment."
If this basis for a healthy civic society sounds in any way pie-in-the- sky, Rogers has proof up his sleeve that his notion of creative leisure works, and works in what seem to be the least promising circumstances. Since the riot on Broadwater Farm, the vast Sixties council estate in Tottenham, north London in which PC Keith Blakelock was hacked to death, Rogers has been part of a team of outside experts and local residents who have nurtured a successful transformation of the estate from a place of explosive alienation to a model of its kind.
"Of course, the architecture's still not great," says Rogers, "but local people are taking responsibility for their own lives and futures. Now we see a new explosion, not of pent-up aggression, but of creativity. The estate has generated its own businesses, its own newspaper, a variety of forms of art and entertainment. It has concierges, a meals-on-wheels service for the elderly and infirm ... sure, it falls a long way short of paradise, but, look, we're talking of an inner-city estate that was a byword for violence 10 years ago and where the security forces squared up to the citizenry. We've come a long way at Broadwater Farm, with residents shaping the beginning of a model of a new covenant between city and citizen.
"The other development that makes me hopeful is the rise of bodies like the National Tenants Resource Centre, a big-hitting national charity based in Chester that aims to help tenants, young people and front-line staff in disadvantaged areas. It aims to develop high-quality training and support for those involved in making communities, in particular urban communities, all over Britain and Ireland work."
For Rogers, architecture is a key means of shaping cities so that they respond to this new covenant. "I passionately believe", he says, "that we must strengthen the public domain in both its philosophical and physical aspects, for the public domain is the crucible of a caring and creative society. The philosophical manifestation of the public domain is the existence of basic human rights, and its physical manifestation is the articulation of these rights in three-dimensional space. City buildings, and more importantly the space around them, between them and even through them, must be as open and as welcoming as possible for all citizens.
Rogers's ideal city is an attractive place and far from being unattainable. Because, however, it is a highly democratic city, it will take some while before we see its full effect in, say, London. Unlike any other European capital, London has no city-wide government. Meanwhile the capital, like Britain as a whole, has witnessed an extraordinary transference of wealth from the poor to the rich over the past decade, which has meant that the most fashionable parts of the city have become ever sleeker and glossier while the poorest (with exceptions, such as Broadwater Farm, which have been put under a national spotlight) have remained shabby.
Rogers has the figures on the prongs of his fork. "Between 1973 and 1993, annual earnings of the top 20 per cent in Britain increased by 10 per cent, while those of the lowest 10 per cent dropped by 24 per cent. This is hardly the way to create a society that people feel proud to be a part of, or can afford to be a part of."
Rogers, of course, has done rather well for himself over the same period, and there are those - not on Broadwater Farm - who would label him a champagne socialist. But there is no need to defend him; unlike architects who have talked of revolutionising the city but have done little about it except talk, Rogers is engaged at grassroots level in the workings of concrete housing estates, as well as making practical proposals, at great expense to his own practice, for ways of making our city centres more pleasurable places in which to live and work. Whether or not you share his vision of a civic culture and a civic society in which we all have the chance to lunch at the River Cafe is neither here nor there; what matters is that the civic culture that Rogers proposes is one aimed at encouraging those who live in cities to be active citizens rather than passive consumers. If, ultimately, every man (woman and child) cannot be as free as St Thomas Aquinas would have liked them to be, we can at least start working with available but misdirected resources to make our cities better places rather than expecting them to do all the work for us.