April, said the guidebook, is the coolest month. It is also the most popular. Petra has only two hotels near its famous site and is fairly remote from anywhere except a deserted section of the Israeli border, so it seemed prudent to book our accommodation before we left London.

'The Petra Forum Hotel is full for the whole of April.'

'Thank you. Can you . . . ?'

'No, we cannot make bookings for the Government Rest House.'

Thank you again. Not for the first time, we would have to travel hopefully and see what happened when we arrived.

In the Middle East, the disparity between a luxury hotel and those a grade down is often vast, so we decided to pass by the two or three 'Hottel Conforts' in the adjoining village of Wadi Musa, and to descend directly on Petra itself.

While I waited in the car pretending to look at maps, my wife approached the Government Rest House. She returned downcast. 'The man said Petra's completely full and we'll have to stay in Aqaba.' (Aqaba is on the Red Sea, about 80 miles away.)

We drove to the Petra Forum Hotel and sat in their car park, reviewing the situation. 'I fear this is a man's country,' said my wife, 'you'd better go.'

Scattering small clouds of dust and sand in my wake, I edged my way to the reception desk. 'Any cancellations?' I asked.

Behind the desk, the handsome young Jordanian shook his head regretfully. He ran a golden ball-point down his ledger. 'You are not a group?'

'No. There are only two of us.'

He glanced fleetingly at my white hair and leant forward. 'Then perhaps I could find you an apartment,' he said.

A ray of golden sunshine pierced the plate glass windows and fell on the desk. 'How much?' I asked.

I shall never know the details of that apartment. My friend was called away by a senior colleague, and when he returned, he said, with a tinge of regret: 'There has been a cancellation, you may have a room.'

Petra is probably the largest stables in the world. Four hundred horses are corralled at its entrance, and having paid a couple of dinar ( pounds 2) to get in, you must part with another four to be hoisted on to one of them and led down the Siq - a narrow gorge one and a quarter miles long, with 400ft cliffs on either side.

Personally, I like the smell of horses. If you don't, you might find yourself thinking that the Siq is aptly named. At the far end of it, you are confronted by a scene familiar from the photograph that appears not only on the front page of your guidebook but in the windows of every travel agent in Europe: the Khazneh, or treasury of Petra.

Petra was fortunate in having as its architects men whose first concern was to overwhelm their visitors with the power and wealth of their civilisation. To do this, they had to challenge the dramatic surroundings that nature had thrust upon them. The treasury, facing the end of the Siq, is the anteroom to Petra and not many things in the world match up to it.

The local Bedouins were doing their best to cut it down to size, however, by creating on its wide courtyard a passable imitation of Hampstead Heath on a bank holiday. Among a variety of attractions was a camel that was made to go through the series of lurches which are its only way of getting up and down, while on his back a succession of customers squealed with delight.

We had left the land of the horse and entered that of the camel and the donkey, and, from now on, the camels' supercilious stare, the donkeys' reproachful gaze would follow us as we picked our uncertain way through the abandoned city that had inspired in Dean Burgon the one and, indeed, the only line that ensured his immortality.

The rose-red city half as old as Time enfolded us, and the deeper we explored, the more evident it became that guesswork would serve as well as our guidebook. For a start, the treasury may not have been a treasury, it could have been a tomb. It is also possible that the other facades carved out of the occasionally rose-red rock could have been tombs, though they may have been temples. They could have had a secular or a religious significance, could have been used for burial or ritual purposes, or could have been houses for the wealthy.

Here, you see none of those tour groups following the umbrellas brandished by their leaders. People just scramble about looking, and as there is quite a lot of it, they can keep on doing this for days. The fit and energetic can climb the rocky paths that lead up jagged cliff-faces to the 'High Places' - the enigmatic name shows how little we know about them - making detours up smaller paths to smaller monuments of equally doubtful provenance.

You can even get lost. We managed this on our first evening. Looking for 'a carved passageway leading to four connecting staircases', we scrambled over rounded rocks like large beehives and into narrow, razor-sharp declivities, we searched for nearly two hours but never found it. Petra guards its secrets well.

It was rediscovered in 1812, when the Swiss explorer and Arabist Johann Louis Burkhard heard of 'some fantastic ruins hidden in the mountains of the Wadi Musa'. He later wrote in his diary: 'I pretended to have made a vow to have slaughtered a goat in honour of Haroun (Aaron), whose tomb I knew was situated at the extremity of the valley, and by this stratagem I thought I should have the means of seeing the valley on the way to the tomb.'

Before Burkhard rediscovered it, Petra had lain deserted since 700 AD, more than 1,200 years. An earthquake that hit Jordan in the middle of the eighth century has often been blamed for this, but tests have since revealed that the masonry from the toppled monuments fell on to virgin sand that had lain there for over 150 years.

This suggests that Petra had already ceased to be a city by about 600 AD, but that cannot be true. There is written evidence that in AD 636, when the Byzantine Christians were defeated by the forces of Islam, the people of Petra lived as happily with their Islamic caliphs as they had lived previously with their Christian bishops.

Who were these pragmatic people who were so reluctant to allow dogma to interfere with trade? They were nomads from Arabia, and before that probably from Assyria. They were called Nabataeans, and they discovered Petra between 600 and 400 BC, infiltrating and gradually taking over the land from the Edomites before them. By the birth of Christ, Petra's population was between 20,000 and 30,000 and it was the capital city of a kingdom.

Yet they were not a warlike race - 'a sensible people, interested mainly in possessions,' said Strabo - and when the Romans finally arrived in force and conquered them in AD 106, the Nabataeans again opted for tolerance.

Petra today is witness to this. As well as an almost complete Roman amphitheatre, the ruins of some baths and a collonaded street, we can see Roman columns and pediments carved by the Nabataeans in bas-relief next to their own Assyrian-type 'crows foot' decorations.

Even 350 years later, when Byzantium presented them with various Christian bishops, the Nabataeans never lost touch with their own cults, though they were polite enough to convert some of their buildings into churches. Born survivors, one would have thought, and not easily unseated. Also, living as they did in a city with natural defences, and on a direct route from Damascus to Mecca, and from Basra to the Mediterranean, not likely to disappear without trace.

Yet that is what they did.

The 1930 Petra excavation team maintained that their disappearance was certainly the result of a natural catastrophe, though this, like most facts about Petra, has still not been generally accepted. So why not put away your guidebook and rely instead on imagination?

There are 12 important wadis in Petra, and the Nabataeans built a tunnel for the biggest, the Wadi Musa, so that it would not flood the Siq. Wadis all over the world are subject to flash floods. Had there been a period of climatic change, could the winter rains make these sufficiently severe to destroy Petra's domestic buildings? And if that has been repeated the following year, and the year after, would it have driven the Nabataeans away?

Now let your imagination run on 400 years to 1116 AD, when the Crusaders built a fort there, whose ruins are still to be seen. It was small, intended for temporary garrisons only, and by 1200 AD it, too, was left deserted.

The collapse of a city such as Petra is difficult to contemplate. Better, perhaps, to think of it at the height of its power, around 55 BC, when Julius Caesar first invaded Britain. Then it would have been an important capital - a royal city with King Aretus II on the throne - a place of influence, swarming with merchants from Araby selling frankincense and silk; traders from the Mediterranean selling olives, skins and salt; the caravans, animals and people jostling each other along its wide roads and through the Siq - just as now.

Walking back through it on that first evening was like walking down Oxford Street on a Saturday morning, only hotter. I was alone and should have been riding a horse.

Foolishly, I had paid for two journeys in advance, and while it trotted off with my wife, I was instructed to wait for its return on the steps of the Khazneh. After about 10 minutes I thought I might as well stroll along the Siq to meet it.

I am not a young man and I take my time. It must have been a quarter of an hour before I realised the meeting was not going to take place. Horses carrying satisfied customers galloped by, brisk young walkers in shorts and climbing boots overtook me, and a kind Frenchman offered me a sip of lukewarm water. By the time I came to the end of the Siq, I was dehydrated and my face was puce. Of my wife there was no sign.

On the way back to the hotel, a large black Bedouin tent just off the path offered me 'The Bedouin Experience'. I tottered in. The tent was cool and wonderful. The warrior who served me insisted I have several coffees, liberally laced with cardamom, and a hookah.

Twenty minutes later, giggling lightly, I parted with four dinars, walked the remaining 500 yards to the hotel, and swayed drunkenly into the foyer. Through a thin haze I saw my wife engaged in conversation with the young Jordanian receptionist. When she caught sight of me, she strode menacingly over. 'Where on earth have you been? The receptionist tells me we can't have a room tomorrow.'

I had been swindled, dehydrated, burnt and subjected to the Bedouin Experience. Now this. 'So in the morning, sir,' said the receptionist, 'perhaps you will be good enough to pack your bags and leave them here before you go out.'

Sadly, we dined and went to bed, and, sadly, in the morning, we packed our bags. That evening, tired and dusty after another day's exploration, we checked our car for petrol, oil, water and tyre pressure in preparation tor our journey to Aqaba. Then we went back to collect our things.

The receptionist bowed politely. 'We have taken your bags to your usual room,' he said. 'However, as we cannot guarantee that it will still be free tomorrow, perhaps you would be good enough . . .'

Of course. So every morning we packed our bags and left them at the desk. And every evening we collected them and carried them back to our room.

Eventually, the time came when we really had to leave, bills and little plastic cards were exchanged, and our bags were loaded on to a trolley. 'We have been very happy here,' I said.

Our receptionist inclined his head. 'Next time, we hope you can bring your group.'

Getting there: Trailfinders (071-938 3366) offers a return fare from London to Amman with Air France via Paris for pounds 334: minimum stay six days, maximum stay two months.

Packages: Middle East specialist Jasmin Tours (0628 531121) offers a six-night Jordan Express package including Amman, Petra and Aqaba for pounds 630; an 11-day Ancient Cities tour, with lecturer, costs pounds 1,229.

Advice: The Foreign Office has not issued any specific advice about travel to Jordan. The Jordanian tourist office in London said that the situation for visitors to Jordan had not been affected by the Hebron massacre. It reports that 'this week we have been busier than ever.'

Further information: Jordan Tourist Office, 211 Regent Street, London W1R 7DD (071-437 9465).

(Photograph omitted)