HONG KONG: EXIT THE DRAGON

Why all the bother, you might ask? Ben Johnson has been working on this vast, painstaking, topographical painting of Hong Kong harbour for the past three and a half years in his west-London studio (it would have taken six years, if he hadn't had three assistants to help him). Why not just take a photograph and be done with it?

Look carefully, however, and you will see that this 12x6ft view of Hong Kong harbour could never be captured on film. It has no fewer than 12 separate vanishing-points, and, while the right-hand side of the painting is washed by an evening light, the left is bleached by the sun at noon.

Come closer. Look. There are no people to be seen in this, one of the planet's most densely occupied cities. No cars either. No buses. No trams. Those boats in the harbour - none trails a wake. Each appears to be anchored, perfectly still.

And this is the point. What Johnson's painting depicts is Hong Kong frozen at its Year Zero, that exact, abstract instant of time at the end of June 1997, between Britain relinquishing its hold over this oriental citadel of Mammon and China taking over.

The process of creating this work has been an extraordinary one, even for Johnson, who is well known for his minutely detailed paintings of urban spaces. He made two visits to Hong Kong, taking photographs; then, with his three collaborators, built up a series of drawings in which 3,000 buildings were recreated in detail. A final edit of drawings - 140 in all - was transferred onto the canvas before being spray-painted with the aid of magnifying lenses (you try painting in the relentless windows of office blocks, each with a different play of daylight from the next). The result is a highly crafted artwork that can, like the great Renaissance set-pieces, be enjoyed whether standing across a room or inches from the canvas.

Nothing in Hong Kong is ever certain. While working on this piece, the team had to paint out buildings that had been demolished; they can't guarantee that other buildings may not have come or gone by 30 June. Which is why the idea of representing this restless dragon of a city in such Zen-like fashion is ultimately so appealing, and so very arresting.

! Ben Johnson's painting is at the Royal Academy, Piccadilly, W1 (0171 439 7438), 13-21 May.