Even if the body was eventually to become more than part-privatised, it would still be subject to government regulation, not least to ensure it did not exploit its monopoly position. Thus, the government would always have a strong influence on its profits, balancing the need to keep faith with the new shareholders (a commitment which might wane over time) against pressures from other suitors to hold down airport charges.

In fact, once we have decent road links to other airports in the region - Macau, Shenzhen and Zhuhai - Chek Lap Kok's charges may come under more intense competitive pressure, anyway. Is the stock market going to induce better strategic thinking into the Airport Authority, or improved corporate governance? Possibly, but the arguments have yet to be demonstrated; it is not obvious where the present arrangement is deficient.

Meanwhile, landing rights are largely the preserve of inter-governmental negotiation. Neither their evolution, nor Cathay Pacific's status as our principal flag-carrier - which are both huge influences on the body's operations - are likely to be materially dependant on the ownership structure of the Airport Authority.

An important factor in Britain was the desire to remove the financing of the erstwhile nationalised industries and public utilities from the public-sector accounts, so that the government could meet its public-sector borrowing targets.

But Hong Kong does not focus on such an all-embracing definition of public-sector financing. Although the initial equity funding of the Airport Authority came from the government budget, it now borrows and invests in its own name, outside the realm of the budget - albeit while still benefiting from its place in the public sector for international ratings. Privatisation, by distancing the body from the government fold and the implicit financing guarantee which that brings, is likely, if anything, to make it more costly for it to raise finance.

Another justification for privatisation in the UK was the desire to widen share ownership among the general public. Most privatisation share issues were tactically underpriced, so ensuring that the mass of small investors reaped substantial short-term gains. Beyond the first couple of years, however, the share prices tended to underperform the stock market as a whole. Investors became sorely disillusioned. In Hong Kong, we must ask whether it is sensible to encourage small investors to buy shares in a single company; too big a purchase could be imprudent in terms of portfolio concentration; too small a purchase might not be cost-effective in terms of the dealing costs of any subsequent disposal.

That leaves as the government's one clear motivation for privatisation its wish to generate a one-off boost to revenue. But this does nothing to resolve the underlying fiscal problem. Investors would need to be assured of an attractive rate of return well into the future. But then, there is a powerful case for the government to hold on to the investment, while seeking to cover its budget deficit by other, cheaper means (such as a bond issue).

The only sure winners from privatisations are the bankers. They will doubtless persuade the government that the exercise is, while eminently sensible, nevertheless highly complex (more so than it need be) and risky. They will go overboard with costly roadshows and marketing schemes. And they will suggest a nice low price to ensure success, while still insisting that they must charge underwriting fees. And, as they pocket the fees, they will comfort us all with a chorus of commitment to Hong Kong as an international financial centre, regardless of whether they have really used local expertise or simply downloaded emails from head offices elsewhere.

The Hong Kong government's interest in privatisation has grown with its mounting budgetary problem. It may not always have seen broader virtue in the idea. There may now be a disposition to identify such virtue, but it is difficult to do so for a public-service body such as the Airport Authority, which would remain under government regulation and continue to have key parameters set by governmental negotiation. The Airport Authority itself may be no worse off for being privatised; but it is not obvious that it would be any better off. As regards whether the government would be any better off, the budgetary justification is at best weak and at worst a diversion - possibly even a costly one - from the real budgetary problems facing Mr Tang. To believe otherwise is no more than clutching at straws. Tony Latter is visiting professor at the University of Hong Kong