It was towards dusk by the time we had given the tourist police the slip and started climbing the pyramid of Mycerinus at Giza. It was Sebastian Barry-Taylor and I and we wore white linen suits.

The 4ft blocks were easy enough to scale because erosion of the limestone had in the 4,500 years since construction weathered cavities or broken off corners so that there were plenty of hand- and footholds. We climbed quickly, looking down at the fat policemen in the desert shaking their fists up at us — but we did not rush it. To slip or stumble would be very dangerous because I could see that once one started falling down that slope there was nothing to stop one from bouncing all the way down. We did not care. We feared nothing.

At the summit of Mycerinus we found carved into the stones graffiti, some of it very old indeed, and the views were spectacular. We looked northeast towards the pyramid of Chephren, with its smooth pinnacle, and beyond it to the great pyramid of Cheops.

As the sun went down, Sebastian and I drank a bottle of good ouzo and smoked a large joint of hashish. After congratulating ourselves and exclaiming about the views and the experience, we went silent in our thoughts as the twilight dimmed. It was one of those moments burned for ever into memory, when I made promises to myself about what I would do with my life.

We were roused by the phosphorus beams of the Son et Lumière show coming on, which lit up the Sphinx and the pyramids for the tourists as the commentary began: ‘You have come tonight to the most celebrated and fabulous place in the world. Here on the plateau of Giza stands for ever the mightiest of human achievements…’

Nothing is for ever, I think now as I stand at the foot of the pyramids 30 years later almost to the day. Before it’s too late, I have set my sights on climbing Cheops, the great pyramid. I do not recall why Sebastian and I did not take it on in 1983 but now Mycerinus, smallest of the three big pyramids, seems an inadequate challenge, not to be repeated. But times have changed.

‘Kufra?’ Asks my Egyptian contact, using the Arab name for Cheops. ‘Impossible. Very expensive.’ But everything comes at a price in Egypt. ‘Money is no object,’ I reply with irritation. Time, on the other hand, is more important than ever. The Egyptian looks me up and down. ‘You can do it?’ ‘Sure,’ I say, stung that suddenly I may doubt myself.

Close up, Cheops is very steep. The limestone blocks in places are seriously eroded, which means they might crumble underfoot and bring on a fall. Cheops is 180 metres high so it’s a long way down. In April this year two Egyptian soldiers rappelling down a rope from a Chinook helicopter hovering over the top fell and their bodies tumbled like rag dolls down the jagged face of the pyramid, arriving at the base pulped and bloody and dead.

I curse myself that now at the age of 48 I find myself assessing risk, which I never would have done at 18. In 30 years I have been shot at and bombed and many other things many times so why fear a pyramid? Why? And then worst of all I find myself listening to an Egyptologist who lectures me against climbing Cheops because of the damage it will inflict on the stones. ‘I feel sorry for the poor pyramids,’ she says — and I realise I do too.

The human stain has already done enough damage so why do more, I find myself thinking. In recent days I have visited a string of lesser-known pyramids — Egypt has 180 of them — that are being systematically destroyed by treasure hunters taking advantage of the current lawlessness and political turmoil. And many Egyptians do not worry about demolishing five millennia of history to build more slums clogged by rubbish, traffic jams and prejudice.

Desperate now, I stand below Cheops, pleading with the stones, gazing up the gradient of rotting boulders. At my back is the hubbub of Egyptian touts urging me to take a camel ride, buy postcards, plastic souvenirs, Pepsi Cola. ‘Sir sir sir see Sphinx see desert where you come from lovely jubbly innit five pound hundred pound I give you for free Revolution price…’

‘Oh, just get lost,’ I say, turning from Cheops, turning from the great challenge of what might have been.