On the wall are five vividly coloured pictures on sheets of sugar paper. Reds, greens, yellows, blacks. Portrait heads, almost all looking directly out at you.
I soon find out they are a kind of totem, a reminder of a lasting responsibility. The office belongs to David Hargreaves, a quiet revolutionary, and one of the most thoughtful writers on education in our time. Hargreaves, though once chief inspector for the Inner London Education Authority, has been in university departments for most of his working life. He is now professor of education at Cambridge University and he was this year appointed joint vice-chairman, with Chris Woodhead, of David Blunkett's standards task force. (Blunkett himself is chairman.) He is thus at the very centre of the government's plans for educational change, in a position formerly held by Tim Brighouse, Birmingham's chief education officer who was constantly at loggerheads with Woodhead and eventually resigned.
But those portraits are from Salford and they are mementoes of Hargreaves's first research, when he observed a boys' secondary modern school. The art teacher there, a pupil of L S Lowry, encouraged the pupils to make self-portraits. The school was next to the docks, where the least qualified leavers could always expect to get a job, in their father's footsteps. Hargreaves's book on the research, Social Relations in a Secondary School (1967), became an educational classic and describes a world of small terraced houses, corner shops, pubs, factories, smoke and grime. (Salford was disguised as "Lumley".)
Now all that has gone, Hargreaves says, as we stand and look at those five portraits. The local schools went comprehensive. The land was cleared and neighbourhoods destroyed. The docks closed. This is now "Salford Quays", with its postmodern offices and apartments and its Lottery-funded Lowry Centre for the arts.
Hargreaves remembers the pupils sharply. They were all, he recalls, fans of the Stones and the Kinks. Only one of them has short hair, "because his parents wouldn't let him grow it". This was non-swinging Salford, where parents still had that power.
"As long as I have an office," Hargreaves says, "those kids will be there. They were in danger of becoming the detritus of society. They'll be in their mid-fifties now. Grandfathers, perhaps. Is it all we've done, down the years: create a replication of families without skills? Unemployed, on welfare, even involved in crime? The biggest challenge is: after two generations, has life changed for the Lumley kids?"
For Hargreaves, comprehensives were emphatically not the answer. Worse: the trauma of reorganisation "was a distraction". Among its advocates, "there was a reluctance to acknowledge that there were very bad casualties". Although we can't now revive the grammar school, the "standard" comprehensive school, he thinks, is over and done with.
In The Mosaic of Learning, published by Demos in 1994, he wrote: "Utopian social engineering - defining an ideal, such as comprehensive schooling or market mechanisms, and then sticking fast to a national blueprint to achieve an ideal - will no longer do. We have had 30 years of it in education and it has not worked well. We need a large dose of what Karl Popper calls the piecemeal approach to reform - detecting weaknesses and failures and then undertaking the necessary experiments and re-adjustments to set things right."
I chip in with some of my own experience. I was at one of the first-ever comprehensive schools. Since then, I have regarded them as just one possible way to run schools: not bad in the semi-rural Pennine valley I grew up in; in cities an almost total mistake. As so often, something that worked well enough on a small scale broke down when you tried to impose it everywhere. Hargreaves agrees. Comprehensives, he says, have turned out to be a very transient stage in English education. And not one that has inspired much love, except among activists and specialists. There have seldom been examples of parents parading with placards saying "Save our comprehensive". Nor will there be.
"The old-style comprehensive looked like a simple solution - consistent, neat and tidy," he says. "But it was ludicrous to pin hopes on an equality of outcomes." Now he looks forward to increasing diversity within the state sector. "Eventually, one secondary school in four will be a specialist school. Within the new education action zones, there should be the greatest experimentation of all. It's no use saying, 'But the most vulnerable kids will suffer'. They always did."
Notoriously, Anthony Crosland, in the early stages of the comprehensives push, said: "If it's the last thing I do, I'm going to destroy every fucking grammar school in England." And it is true, as Hargreaves wrote in The Challenge of the Comprehensive School (1982), that "sec mod" had become "a term of opprobrium". But, as he also pointed out, "most teachers and parents cling to the rhetoric of meritocracy". Nor is this perverse. "Popular adherence to meritocratic ideas is grounded in experience." Neither Michael Young's early warning, in The Rise of the Meritocracy (which, in 1958, launched the word into the English language), nor later research has ever managed to dent this common-sense judgement of what is the best way to help children get on in the world.
Hargreaves's great regret is that the 1944 Education Act's hope for a third way of technical schools, flanking grammar schools and secondary moderns, was never delivered. Specialist schools may start to repair that damage. "If the Japanese and Germans have kept an apprenticeship system going, it relates to their system of technical education," he says.
"At this point in our history," Hargreaves has written, "we must enter once again into the debate that preceded mass schooling over a century ago: namely, what sort of society do we want to create, and how can the education system help us to reach such a society?"
He describes himself as a libertarian. "There are some dilemmas you can't resolve. And that isn't bad. It would be a very unpleasant world if we ever thought we had the answer to everything."
To Hargreaves, many on the left take a highly reactionary view of education, trying to hold down on choice. "This is doomed to fail." He makes the analogy with broadcasting. "Once, everything was centralised, up here," and he waves a hand in the air, "with the BBC. Now you have multi-channel media," and he waves his other hand towards the bookshelves, "with diversity and choice. In education, you are tracking along that same line. You can't get everything up into that centralised cell. It could never work . . . people want the education service customised. Schools are still a very 19th-century institution.
"My parents, God rest them, never expected any choice about holidays or about where to go and eat. The world has changed, and we have to respond."
Behind the 60-year-old Hargreaves's overlay of received pronunciation, you can hear the original Lancashire. His father was a semi-skilled engineer in the textile town of Bolton, who slipped down the prosperity scale through a succession of accidents. "We were respectable working class, but really rather poor." He, and his brother and sister, went to Bolton School - direct grant then, independent now. "I didn't know the class background of the other pupils, nor did I care. When I was at ILEA, the best schools were those that avoided imposing pathological models on pupils in terms of their background." He says he never felt the tensions between school and home that Richard Hoggart and Brian Jackson chronicled in The Uses of Literacy and Education and the Working Class, books that gave much of the emotional drive to the destruction of local grammar schools.
He sees the education of the future as a life-long system of networking and re-training. When he was in California recently, the Catalan sociologist Manuel Castells - "the new Weber, don't they say?" - told him that the average West Coast job now lasts 3.2 years. It is no longer good enough, he thinks, to argue that "equity means uniformity of mission".
"Everything should be tried out. Schools should mix public and private services. A national curriculum means we can be less anxious about, for example, religious schools. Variations in schools, and in teaching, can be encouraged." The left, Hargreaves argues, cannot ignore "declarations of human rights in the field of education". He adds that "even on the left, much has changed". When he recently met one of the inner London teacher militants whom he remembers from the days of guerrilla strikes and general non-cooperation in the mid-1980s, "he gave me a business card with his mobile phone number on it".
Does he get on better with Woodhead than Brighouse did? "You bet," he says. "You've got to remember that, as an inspector, you see things other people don't. Woodhead says that teachers have plenty of people to protect them; they're all right. Many children, and the least articulate parents, have nobody. I agree with him on that."
I go out past the Salford Five, and down the stairs into the sunshine. On my way to the station, I walk past Thomas Hobson's celebrated freshwater conduit - endowed for the public benefit from the profits of his ostling and carrier service. It occurs to me what Hargreaves's core principle is. As the way to run an education system, Hobson's Choice is no longer good enough.
The writer is a Senior Fellow of the Institute of Community Studies