The diplomat travels not just because he enjoys travel, although it is as well that he should do so since he is fated to spend much of his professional life on the road, but because it is an essential part of his job. He travels to and from his posts abroad, he travels around the countries to which he is posted and, even when he is based in London, he tends to be caught up in the constant round of international meetings of which the web of modern diplomacy is composed. It all sounds pretty glamorous but, like so many other forms of modern business travel, it can easily become exceedingly humdrum if you let it. Similar airports, with similar flight delays, similar hotel rooms in impersonal international chains, and similar meeting rooms are not the stuff of which romantic travel experiences are made. The modern diplomat who wants to enjoy and benefit from his travel is going to have to work at it, not just sit back and have it ordered up by the travel section in the Foreign Office or his embassy.

Diplomatic travel begins with the journey to your posting, which can be extremely banal if you are heading for a western European capital or merely crossing the Atlantic, or potentially a bit more interesting if you are going further afield. Of course it will still be a far cry from the journey described so delightfully by Lady Macartney in An English Lady in Chinese Turkestan, when she set off in the nineteenth century with her husband, the British Consul General in Kashgar: they travelled on the newly completed Russian railway system to Tashkent and then covered the final leg of their journey by riding hundreds of miles over the Pamirs to reach their destination.

One personal rule I did try to stick to was always to travel to your post overland. This made for some very interesting experiences, particularly driving out to Tehran in 1960 - which involved some circuitous avoidance of East European Communist countries, then out of bounds to mere travellers - and through Eastern Turkey and Western Iran where a hard-top road was a rarity.

My system finally broke down after 25 years, when I was sent first to Washington and then New York, but I did manage a kind of revenge by returning on retirement from the latter via a long land journey through China and Central Asia. The object of going by land to your post is not mere whimsy, it is to try and arrive for the first time with some idea of what the country and its people look like and live like, and it is something you are unlikely to achieve on the road between the airport and the embassy.

Once you are in your posting, the opportunities for travel are greater, but again they need to be carefully planned. It is all too easy to get trapped into the bureaucratic grind of modern diplomacy - a far greater pitfall than the fabled cocktail party circuit, now largely a thing of the past - producing paper for the slave-drivers at home and missing the opportunities to get to know the complexities and attractions of the country you are in, not just its government. Once again it is a good deal less easy than it used to be to take off for a few weeks or even months into the wild blue yonder, as Sir Fitzroy Maclean chronicled in Eastern Approaches, a record of his travels in the Soviet Union in the 1930s, or as Hugh Carless did when he accompanied Eric Newby on A Short Walk in the Hindu Kush in the 1950s. Nor are there many opportunities such as I had in Afghanistan between 1961 and 1963 when I was grandly titled the 'Oriental Secretary' and managed to persuade my ambassador that I was more use to him on the road than in the office. It seems odd to think that we used to camp in the Panjshir Valley or catch trout at Bamyan in the shadow of the 50- metre-high statues of Buddha, where now the various factions of Afghanistan's eternal civil war are slugging it out.

It is almost equally odd to think that, as a Persian language student, I was encouraged, i.e. paid, to travel around southern Iran, on the condition that I went by public transport, which meant bus if I was lucky and the back of a lorry if I was not. It brings home the reality of the fact that war and instability are as often rapidly closing off places to which the diplomat may travel, just as technological advances are opening them up. But political developments are not always obstacles, as is demonstrated by the scope now for travel in China where not so long ago it was hard to get permission to go outside Beijing.

It would be nice if the diplomat only had to plan his own travel, but it is not so. One of his more demanding and thankless tasks is to act on occasion as a cross between a travel agent and a courier. A spell as a private secretary comes the way of many, and that is when qualities such as improvisation and endurance are put to the test. It is not just a question of getting your boss to the right place at the right time, it is a matter of getting there in the right frame of mind, often a good deal less easy. I worked for four years for Christopher Soames when he was a European Commissioner, during which we travelled pretty widely. One of his main characteristics was not simply to insist on absolute punctuality, reasonable enough when catching aeroplanes or calling on Prime Ministers, but also to avoid ever arriving anywhere more than 30 seconds ahead of the appointed time. The second part of the equation caused his private secretaries a good deal of anxiety, particularly when travelling in Asia and Latin America, or trying to calculate in advance the density of traffic between the airport in, say, Paris or Rome and the Foreign ministry. His other principal characteristic as a traveller was to insist that, if he was to go sightseeing - and he was not averse to that - then there had to be a three-star restaurant handy in which to recuperate. Travel as a private secretary is not, on the whole, life-enhancing, though it can provide a good deal of amusement, particularly in retrospect.

The most daunting challenge for the diplomat as traveller is to make something of those one-day stands which involve rushing from airport to meeting room, endless tours of the table, which have nothing to do with travel, and then a rush back to the airport - which is now the general form of modern diplomatic life. It is not easy to do. The frequency of airline flights makes it hard to convince one's employers that one simply had to travel the night before. The tendency of all international meetings to conform to a Parkinsonian law, which ensures that they last slightly longer than the time available for them to complete their work, is another complication. Nevertheless the really determined diplomatic traveller, whether his tastes be cultural, artistic or merely gastronomic, can usually manage to squeeze in the odd visit to a cathedral, an exhibition or a restaurant if he is sufficiently ruthless. Just occasionally the country caters for the travelling propensities of their guests by arranging the meetings in surroundings of beauty and interest; more often, unfortunately, they calculate that you will get more work out of people if you prevent their surroundings from being too attractive. Certainly, of the many meetings of the European Council I attended while I was dealing with the European Union, a great deal more fell into the latter rather than the former category. It took a hardy spirit, when Mrs Thatcher was leading the British delegation, to slip away, say, to that fascinating modern museum in Stuttgart.

But of course the diplomatic traveller is not limited to professional travel, important a part of his life though that may be. If he is really bitten by the bug and if he can persuade his long-suffering family to share his passion, a lifetime of diplomacy provides some ideal jumping-off points for wider travel. Brussels may not be exciting in itself, but it is a remarkably good base from which to travel the European continent. New York is quite exciting for a traveller, but so is the possibility of using it as a base for visiting the furthest corners of Latin America. There are few better ways to spend a tedious afternoon in one of those subterranean meeting rooms at the United Nations than in planning how to get from Machu Picchu across Lake Titicaca to Bolivia (the answer: take the train from Cusco to the lake and hydrofoil across it).

So do 35 years or so of diplomacy dull the taste for travel? In my own case apparently not. The list of places still to be visited and 'vaut le detour', in Michelin's inimitable phrase, seems if anything to grow longer. A willingness to rough it has certainly diminished, but so, fortunately, has the need to do so. The real challenge is to resist successfully what one could call the homogenisation of travel, the tendency to sell travel as McDonald's sells hamburgers. The diplomatic travellers should be in the vanguard of consumer resistance to any such tendency.