Methinks what happened is that Mr Zhang had a political decision to make. He wanted something that would obligate Hong Kong to pay the lion's share of the cost for this bridge to Zhuhai and Macau because we in Hong Kong are reckoned the soft touch and Guangdong doesn't really want the bridge anyway.

He therefore wetted his finger, stuck it in the breeze and the reading said that a 64 per cent economic benefit ratio was the figure that would find eventual acceptance with the least political disturbance.

But was an economic benefits study actually done? Has there even been a proper feasibility study? Has anyone put together any formal financial estimates?

I strongly suspect that the answer in all these cases is a flat No. We are building this new bridge because a few tycoons with interests across the Pearl River have the ear of our government. We are also building it because construction contracts mean money for contractors and everyone will then be happy, at least among the people who have any influence in political matters.

Thus if any private developer who wins the contract for building and operating the bridge does not believe that toll income will be enough to compensate for the estimated HK$60 billion cost and bids some lower figure, then Hong Kong will cover 50.2 per cent of the shortfall, Guangdong 35.1 per cent and Macau 14.7 per cent.

Let's have it straight that there will be a shortfall unless the private developer wishes to bankrupt himself. To pay off the debt and make his shareholders welcome his participation he will need at least an 8 per cent annual return on this investment, which would come to HK$4.8 billion or HK$13.15 million a day after operating costs. Let's start with some signposts to Nevernever Land.

It particularly won't happen because our port will not need this bridge by the time it is built. As the chart shows, Pearl River Delta ports now handle more ocean cargo than Hong Kong does. The business is going back across the border because it never really made sense to have southern China's major port in a cross-border urban territory at the end of a long traffic-clogged roadway.

Bear in mind also that what little growth in business our port still shows comes in the context of a quadrupling of mainland foreign trade over the last six years. This trade boom will slow down at some point and our port's business will then decline.

It will probably decline anyway with ever more manufacturers in the Pearl River Delta complaining that they have to shut down or move away because of rising costs.

Even if it were not so, has anyone in our government asked what responsibility we bear to manufacturers on the mainland? Why are we obligated to use Hong Kong taxpayers' money to assist the industrial development of the western part of the delta?

And why do we think that vehicle transport across a bridge is necessary to get containers from that region to our port when there is already a very efficient river transport system to do it? It all defies common sense.

It defies it even more in tourism, which has been another argument for building the bridge. What the bridge will do is grant Macau the huge favour of a top-class transport system to ferry tourists from our airport to Macanese casinos.

The bother and difficulty of getting to Macau is still one of the drawbacks of these casinos. What we will now do is hollow out our own tourism, exhibition and convention business by solving this problem for Macau at our expense, solving it for Zhuhai, too, in case Macau cannot handle the entire exodus from Hong Kong. This bridge will not bring us tourists. It will take them away from us.

And if the official argument is that we are doing all this for integration with the Pearl River Delta, could someone please explain why we should want to integrate this way when Guangdong officials do not?

They maintain a cross-border vehicle licence racket that severely restricts issuance of these licences in order to boost their value to as much HK$500,000 apiece.

These people have already made fools of us with their licence restrictions by choking off traffic on the recently completed Western Corridor. They don't want another crossing. It gets in the way of their lucrative little game. Why are we to bash our heads against a wall like this once again?

But I shall be positive and hope that common sense returns. If so this bridge will not be built. It's a bad idea on every count.