MONDAY. Here I am in berserkly Berkeley. After two sabbatical months, I can find my way around at least geographically.

My office in the Center for Studies in ÖйúAƬ is at the heart of the magnificent campus. Scents of jasmine and eucalyptus mingle as they waft down from the hills.

Housed in the rooms around the central seminar room and library is an impressively varied bunch of research associates. They include two historians from Japan, a ministry of education man from Korea, a former minister of science in Hesse, Germany, and an Englishman living in France who appears to know everything about every system of ÖйúAƬ in the world.

We have "brown bag meetings". When I was told about them, I tried to be funny - I can increasingly see why the English are regarded as quaint - by asking: "What's the brown bag for? In case I'm sick?" "No," they said, "it's for your lunch." We bring our sandwiches in a bag and munch while we discuss such issues as teaching versus research and finance versus autonomy.

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TUESDAY. My daughter rings from Amsterdam (she has just finished her MA in film studies there) and I try to describe laid-back Berkeley, the beautiful campus, the wonderful libraries, the impressively knowledgeable colleagues, the lively seminars (sorry, brown bag meetings), the thousands of students strolling purposefully around, the cafes with waiters all apparently reading Tolstoy in well-thumbed paperback. "It sounds just like Amsterdam," she says. I see her point. It is certainly not like London.

As I left University College London, we were just beginning to reel under the threat of a further 7 per cent cut in Government funding. As I arrived here, the University of California was trying to cope with a 6 per cent increase in funding from the state of California. The university here has had some years of budget cuts, but it is a different world.

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WEDNESDAY. I start the day by drinking coffee on the balcony of my apartment, looking across the bay to the Golden Gate bridge. As I walk to the library, an elegantly dressed black lady with Dame Edna glasses says to me: "You're looking good." I used to be fazed by the random conversationality of passers-by, but I have come to realise that they are just expressing a democratic friendly sense of well-being, and so I smile and know what to say: "You're looking good too." On the campus, a distinguished-looking silver-haired white man is walking around shouting at intervals of about a minute. "Do you know that Adolf Hitler was a baptised Christian?" I do not know quite how to deconstruct this sort of thing. Spend all day in the library; it is dark outside when I emerge. It is wonderful not to have a single committee to sit on, no boards of examiners to attend, no departmental meetings, no lectures to give, no essays to mark.

THURSDAY. My daughter seemed surprised that I should come here to begin to write a history of the British university system. Virtually every day I have been here I have talked to Sheldon Rothblatt and Martin Trow, both professors here, and two of the world's leading scholars who have written about British universities. And frequently bringing his brown bag to our discussions is Clark Kerr, the former chancellor of Berkeley and president of the university who was sacked by governor Ronald Reagan in 1967. Clark Kerr then famously said he was "fired with enthusiasm", and now in his 80s, he is vigorous, lively and immensely knowledgeable. I spend the day reading more and more about American universities. In the evening I attend the Faculty Club to talk after dinner to the "United Kingdom Seminar". I cannot remember what I talked about as I spent the entire time admiring the wooden arts and crafts building designed in 1903 by Bernard Maybeck , whose buildings adorn Berkeley.

FRIDAY. Go to the new University of California, Santa Cruz. Eat a delicious corn chowder on the terrace of Cowell College, looking out across fields and woods to the Pacific.

It seems extraordinary to walk through a redwood forest following signs to the library. The campus architect shows us the plans for rebuilding Kresge College, the most feely-touchy of the colleges in the 1960s. The students still look pretty hippy, but they want their own private space rather than the open-plan group living envisaged by the the college creators. The architect is putting in partitions and his blue prints symbolically chart the end of a utopian dream. At night I make a point of having dreams that are Californian and not utopian.

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SATURDAY. Californian dreams continue with Berkeley's secondhand bookshops and more of Maybeck's buildings. Can there really be no such thing as a foreign country? Neither these reflections nor my Californian dreams stop me beginning to have London nightmares. It will not be long before they are a reality.

SUNDAY. Visit Napa Valley and its wineries, post-modern villas, modern art collections. Delicious lunch and pink champagne. For the moment the dream goes on. I have done more work in the library and at my computer this week than in any one week for years. Why can't sabbaticals last forever?

Senior lecturer in economic history, University College London, and public orator of the University of London.