In the last few years​ , I have fallen in love with brick. I carry in my head a taxonomy of drainpipes and cement and scaffolding; I’ve become, in the last decade, a night climber. A while ago I climbed up the side of Battersea Power Station, up the great smoke stacks, to look at the world as it lay below. It’s the largest brick building in Europe, and I wanted to see it before it disappeared.

It’s easier than you would think to get onto the walls of Battersea. You shin up a lamppost and drop down over a wall and there’s the power station, huge and already part dismantled, lying like an upended dinosaur in a sea of churned earth. I went with a friend – a barrister with anarchist leanings and the kind of physical daring I’d previously seen only in soldiers and toddlers – who had been to Battersea before. ‘The guards are fine. The worst that can happen with them is you get put in a cell for a night. But if you see a dog, get up high, because they’ll bite.’ Which is fine, except Battersea Power Station is next door to Battersea Dogs Home. Every few minutes I heard a bark and froze, ready to abandon my friend and run for the wall.

The first part of the climb isn’t hard. That night there was scaffolding, as easy to scale as a jungle gym, and we went silently, not speaking and trying not to breathe loud enough to attract the possible dogs. I left behind a little blood from my knuckles, but not much. The view gets more intricate, and the sky grows larger, as you leave the other buildings behind. Every few levels of scaffolding, pigeons took off. Battersea doesn’t look like a skyscraper, but it’s more than a hundred metres high. You come out at the top by pulling up over a ridge of bricks and scaffolding onto an expanse of grey slate, big as an empty town square, between two of the great white chimneys.

Giles Gilbert Scott believed in thoroughgoing industrial beauty. We found as we explored that the insides of the four great smoke stacks are lined with green-grey iridescent ceramic tiles. I’ve seen few things as beautiful; you could build a wall in them and outdo a king. Scott must have known that almost nobody would ever see them, but their presence is a bold and lovely fact. There are, too, flourishes built onto the walls, constellations of bricks like the work on the side of a cathedral, up near the top and too high to be seen from the ground. It’s this, the hidden life of buildings, that makes climbing seem a reasonable wager, to bet your safety against the promise of beauty.

At the very top, at the foot of the chimney, we decided it was high enough to risk noise. The air is sharper and colder up high. We played music, and danced a bit. Climbing the chimneys is a different enterprise; there are iron rungs set in the brick, like a ladder, but they are flush against the brick and were ice cold. I tried anyway. The river, seen from those chimneys on a cold clear night, looks sketched out in golds and silvers; it is a thing worth hunting for. But the wind was picking up enough to make my eyes water too badly to see, and my feet and hands were growing numb, so I climbed down without reaching the top. Another night, I hope.

Battersea, in fact, is a fairly simple climb, made ready by the builders who are destroying it. I began night climbing at Oxford, with a few friends, crawling out of windows and up drainpipes – the circular ones, never the more ornate square ones, which are likely to peel away from the wall – to see the city we were still in awe of from above. Oxford can be an uneasy place for teenagers not reared on self-belief and champagne, and it was emboldening to walk it from above; the closest you could get to conquering the city. But it was more than that; I have always loved to be up high, and I have always loved the electricity it puts in the blood.

Night climbing, when it goes well, works on the joy of quick and necessary decisions, on improvising in the two seconds in which your stomach and brain are in conflict. It is unmooring your sense of fear and self-preservation from your sense of hope and danger and adventure. There are moments that can’t be replicated anywhere else; nowhere at ground level offers the same pleasures as sitting with your back against chimney pots, or walking the apex of a rooftop, or looking down on the Tetris pattern of masters’ gardens and college quads. I discovered that All Souls has gargoyles with moss growing on their tongues. The former warden John Davis tells a story about the historian David Cox, who, as an undergraduate, climbed onto the Codrington Library and stole the weather vane from the Christopher Wren sundial. When he was elected a fellow, he climbed back up and replaced it. Nobody, as far as he could tell, had noticed its absence.

The world is huge up high. I’m not daring in most things – I cross roads at the green man and wear my seatbelt on a plane even when the captain has switched off the light – but heights offer a brick-dust puzzle-solving shot of joy that nothing else matches. Climbing walls make good rough drafts, and smell enticingly of chalk and human palms, but they’re not like the outside. Outside, the most real danger is from yourself. Philippe Petit, who strung a high-wire between the Twin Towers in 1974, was wise about vertigo. ‘It cannot be done all at once. To overpower vertigo – the keeper of the abyss – one must tame it, cautiously.’ When I stand on the edge of buildings I’m not afraid I’ll fall, I’m afraid I’ll jump. But so far I’ve had no accidents beyond a few twisted ankles, blistered fingers, and some deepish grazes that left my knees and shins patterned for a few years like a Turkish carpet.

‘I neglect God and his angels,’ Donne wrote in a sermon, ‘for the noise of a fly … a memory of yesterday’s pleasures, a fear of tomorrow’s dangers, a straw under my knee, a noise in mine ear, a light in mine eye, an any thing, a nothing, a fancy, a chimera in my brain, troubles me in my prayer.’ He was right: but if you want to know what it is to have one thought only, go climbing without ropes. I am not elegant on the ground, but on a wall I feel I am and there is nobody who can see well enough in the midnight to contradict me. It’s a cheap high but a very real one, to swing so close to disaster. Night climbing is better than most sex. Whipplesnaith, the author of The Night Climbers of Cambridge, puts it best: ‘If you slip, you will still have three seconds to live.’

I will never be anywhere near as good a climber, though, as Whipplesnaith was. His real name was Noël Howard Symington and he recorded the exploits of the night climbers in the 1930s in a book first published in 1937 and recently reissued. The photos in it are remarkable: I wear flexible clothing to climb, black leggings and dark sweaters; the photographs show young men in brogues and spectacles, shirts and ties and corduroy trousers fastened high with a belt. The book evokes a certain kind of student – adult schoolboys with architectural jawlines and the right amount of money. Boys in love with one another’s brilliance and daring. Many of them went on to be true mountaineers; Wilfrid Noyce climbed in the 1953 expedition to Everest, and Symington went up Mount Kenya. Sometimes barefoot, in their respectable trousers, they climbed many of the hardest walls in Cambridge, and the book offers a guide for those coming after them: ‘Your feet are on slabs of stone sloping downwards and outwards at an angle of about thirty-five degrees to the horizontal, your fingers and elbows making the most of a friction-hold against a vertical pillar, and the ground is precisely one hundred feet directly below you.’ There are diagrams, carefully labelled: ‘Second overhang with parapet just above. C: Chess-board, at which point the stone becomes crumbly.’ It sounds so efficient, but there are moments at which their youth is very obvious: ‘This climber has developed a peculiar habit of saying “Goodie, goodie” at the end of every climb.’ Best of all, though, is the unexpected clarity with which Symington explains why they put themselves at risk: ‘The imagination, through its violent and constant use in climbing, receives a permanent increase in strength.’ And:

There is a kind of fear which is very closely akin to love, and this is the fear which the climber enjoys. It is, to use a contradictory term, a brave fear; a fear which announces its presence, perhaps very loudly, but raises no insuperable barrier to achievement. The climber enjoys being frightened, because he knows fear is no impediment.

A few years ago, there was a question in the All Souls fellowship exam: ‘What should we do with Battersea Power Station?’ Nobody who has seen it up close could believe that the solution the developers have come up with – flats, a shopping centre, a yoga studio and treatment rooms – is the right answer. The smoke stacks will be knocked down and rebuilt, without the ocean-grey ceramic to their insides. I am not, I know, clear-headed and politically unbiased on the question – but as a child I wanted to fly on dragons. The vast, brutal beauty of Battersea is the closest I am going to get.