It is safe to say that I won't be flying BA

THERE IS, though we do not often notice it, a Modern Underground - an underground composed not of fugitives from the law but of fugitives from terror and criminality. Salman Rushdie, who, it emerged last week, has been banned from travelling on British Airways, is not its only member. Others have been told: your name is on a list; you must leave home for good, vanish from all your normal haunts, let no one know where you intend to live. There are alternative deals - some elect to live in protected compounds, like the old Communist nomenklatura. Others spend short terms in the category of Protected Persons, to re-emerge soon afterwards when the coast seems to be clear.

Only royalty and the politicians, it seems, are barred by their professional requirements from disappearing entirely into the Modern Underground - and it is in their ranks that the terrorists have found their victims: Mountbatten, Ian Gow. These were hard people to protect. Any secretary of state for Northern Ireland knows that he has embarked on a highly dangerous career and must adjust his expectations accordingly, just as any Northern Irish MP must. But you could hardly expect to be both a community politician and invisible. MPs must remain a presence in their constituencies. The Prime Minister must retain his house, which must therefore be guarded.

So how many people live in the invisible wing of the Underground? Totting up the figures, I was astonished to find that, without having gone out of my way to do so, I had met five people currently living in these conditions. If we add all judges and magistrates in Northern Ireland, plus some controversial industrialists, the figure must reach several dozen, at least. In some cases there are agreements that the press makes no reference to their mode of life, so a figure could be both well-known and not known to be in hiding.

Royalty and the politicians are the most difficult to protect. It is perfectly possible to find out where the Queen and her relatives will be most days. The whole world knows weeks in advance that there will be, say, a major summit or some round of Gatt talks that will require the presence of a particular politician.

But the denizens of the Modern Underground always travel unannounced. Their enemies are not to know where they are coming from or where they are going to. This is one of the principal sources of their security.

It would be shocking, would it not, if British Airways had ever said to an MP or a member of the Royal Family: Look, we understand that you are a potential target, and therefore we cannot guarantee your security. Supposing BA had said no to Ian Gow, who had made the choice to forgo the underground way of life? Supposing it was to say so to - no] this is unthinkable - the Princess Royal: 'Sorry, love, we can't safely take you today or any other day, under any circumstances.'

One thing that people might immediately say on learning that BA has barred Salman Rushdie is: is it implying that it does not know how to secure a plane? Because that is what it would sound like. After all, there are supposed to be well-tried routines for checking people and objects being put on a plane. If these procedures are not sufficient, then nobody on any BA flight is safe. Any plane could be made an example of at a time when, say, the British have been involved in some military exercise. And how could any British Airways passenger be certain that he or she was not travelling on the same flight as, say, some obscure minor politician who has just made an implacable enemy.

Of course, British Airways has not been saying publicly to high-risk royals or politicians that it cannot carry them. What it has been saying privately for the last couple of years is that it cannot take Salman Rushdie. During this time, while a dozen other airlines have seen no problem, BA has said that to take Rushdie would be to put its passengers at risk.

The Foreign Office does not see that there is such a risk, nor therefore do the security services who advise the Foreign Office. John Major is against BA's stance. The police who protect Rushdie believe that there is no risk - after all, they have designed the conditions under which he exists in the Modern Underground, its most celebrated, unwilling member.

The reason why this story came out is that, after three unsuccessful official attempts had been made to persuade British Airways to change its mind, there seemed not much point in keeping the matter quiet. Second, the unwillingness of BA had begun to infect other airlines, and Rushdie was afraid they might begin to think that BA knew something the other airlines did not.

It seemed right to bring the matter into the open and seek active support from other airlines, which was what, indeed, was immediately forthcoming from Air France. Its attitude is that Rushdie can travel with it any time he pleases.

As for what our attitude should be to British Airways, I think there are two logical positions to take. One is to write to it and say:

Dear British Airways, I accept that you cannot guarantee the security of your passengers if Salman Rushdie is on board. But there are quite a lot of other people who fall into a high-risk category. How am I to be sure that there will be no royalty, no risky MPs, no Ulster magistrates on board your planes in the future? Will you publicly undertake never to allow, for instance, the Secretary of State for Northern Ireland to fly the flag? You have not done this so far - why should I expect you to be consistent over security in the future? If as I accept, you cannot securely fly one of the most securely protected of my fellow citizens, why should I feel that any of your planes is secure? I am sorry to say this, but until you improve your security I cannot fly with you again.

Best wishes, etcetera, etcetera.

The second logical position (the one I favour) goes as follows:

Dear British Airways, I see no reason to believe that there are not perfectly adequate security procedures at Heathrow and Gatwick and the other airports from which you fly, nor have I found your own airline lacking in security consciousness. I don't believe that you could not, in most circumstances, get Salman Rushdie quietly on to one of your planes, nor do I believe that, once on board, his presence would affect the security of the plane one jot or tittle. What I do believe is that you are operating a policy that is profoundly discriminatory. I just think you stink, and that is why I intend to boycott your airline until you change this policy.

Yours etcetera.