Gardening: Maybe it's because I'm a sentimentalist

In the Smoke the other week, I packed in rather too much. I caught the first showing of Golden Balls, a funny and touching film about a north African making his way by crookery and sex in the Spanish building trade. I carried away a sense of solidarity with the anti- hero, mostly because he loves Julio Iglesias. In Spanish eyes, this defines the hapless builder as tacky, whereas I think his devotion speaks of an absurdly romantic nature railroaded into sentimentality.

The next day, I took in London, a curious, gloomy film in which Paul Schofield, in his passionate drone, narrates Patrick Keiller's strange 'psychic landscaping' of the capital. The film looks extraordinary: it was shot on a restored Eclair news-camera which combined a sort of matter-of-fact view with a capacity to make every frame crawl with detail. London is pinned to the screen as though it were a rather ordinary moth which on close inspection is seen to have glamour buried in its drabness.

The film's thesis is, I think, that the Tories have lent their suburbanite hand to an enterprise that London has always been good at: they have intensified its capacity to alienate. They have snuffed out the possibility of the romantic finding enough oxygen. The bohemian, for instance, is extinguished because there are no cafes. The film implies that you cannot dream in London because we have all been turned into sharks and, once gainful activity ceases, we sink.

This may just be an orgy of nostalgia, an elegy to the London many of us experienced in the Sixties and Seventies. We had cheap garrets and could wander in the magnificent urban ruination of the docklands. We could hang out in kebab houses where the prices as well as the food seemed Mediterranean. Being young, the city seemed undemanding. It seemed organic because we were so vigorous. But even now, I am struck by the warmth that can be drawn from its anonymity. I am still, romantically, capable of seeing it as a life-support system that refuses to wear its heart on its sleeve.

London's commentary - though that is too weak a word for the script of what is more a drama than a documentary - quotes Baudelaire: 'Romanticism is precisely situated neither in choice of subjects nor in exact truth, but in a mode of feeling.' A romantic tries to discover what feeling will tell him about the world when thought has reached the end of its rope. A romantic is devoted to denying or enriching facts.

I take this to be what was happening to art in the 18th and 19th centuries, when, following Claude, painters moved into a new phase of seeing nature. They seemed, in their naturalism, to be just observing, but actually they were psychic miners. At times, romantic painting looks like a celebration of nature and man's place in it. Its darker message becomes apparent when you sense that mankind is preoccupied by nature, the Great Other, because of our uneasiness.

Over and over, we explore nature to see if it will tell us whether we are doing well or badly.

Walking around the National Gallery's 'Friedrich to Hodler' show (subtitled, 'A Romantic Tradition'), you are confronted with contradictory images. For romantic painters, nature's vastness became impressive and reassuring, rather than intimidating, at just the point when man was mastering and diminishing it.

Examples of the tension were everywhere. There was Caspar Wolf's painting of a waterfall cascading hundreds of feet, with minute human figures carrying parasols at its foot. But was nature convivially showing off to these puny geniuses, or was it resentful of their intrusion? Nearby was a painting of a new bridge being erected in a vast valley. Was the bridge supposed to represent man's progressive harmony with nature, or was it an insult to the wildness all around?

One's interpretation may just as well be left to one's mood, in true romantic spirit. I have been reading Laurence Whistler's account of his marriage to Jill Furse, the brilliant but chronically ill actress. It is one of the great love stories of this century. At one point, he says: 'The happy are like the successful in this, that they own whatever landscape they inhabit.' As Whistler faced London life without Jill after the war, he felt 'of no account on the shiny pavements'. He had become dispossessed.

One can take this in an ordinary, personal way: whether London seems cheerful depends on whether you are cheerful. But the remark works just as well for the whole human species. We turn over and over in our minds whether we have any right to be happy about the scene around us. It is a truism that, 25 years ago, the pictures from the Moon lobbed us an enormous question. And for half a millennium, at least, it has been taking a greater and greater effort of will - of feeling and thinking - to see that what man does is always natural. To distort Whistler a bit: the more man is successful, the more he courts the alienation of the unhappy.

A lot of this is not factual but a matter of perception. In 1976, we had a long hot summer in London. But then we simply said: 'Phew, what a scorcher.' Now we say: 'God, look at the smog.' Things race ahead. Osbert Sitwell saw London's older sort of smog, the pea- souper, as an indispensable part of the city's romance. He doubly felt the connection: his country seat was built on wealth from coal sent to the city.

I don't think traffic and pollution have changed much in London, but I feel far more jumpy about them. I must take to my bike again, much as I like the urbanity of buses and taxis, and dislike the moral superiority of cyclists. I still romantically feel that London belongs to me, and even depends on me. Or am I just being sentimental when I feel I can't shrug my shoulders at the beast, but must help it to live?