LONDON - When men speak of the future, the gods laugh, runs an old Chinese proverb.

In the aftermath of the 1989 Tiananmen crackdown, China's policy of reform and opening seemed to many to be in peril. Conventional wisdom was that it and much of the communist world were retreating into isolation, threatening a new Cold War.

But within months the Berlin Wall fell, and soon the Soviet Union evaporated. And China changed at the speed of light.

A country where phones were rare 20 years ago now has more internet users than any other. City skylines have morphed from grim barracks into glittering skyscrapers and a still officially Marxist society has become one of the most unequal on earth.

After 1989 China produced perhaps the biggest economic boom in history, until it could even lend America enough cash to ruin itself. In June 1989, all that would have seemed mad fantasy.

Then, the pundits had misunderstood what was happening. The democracy or human rights demanded by the 1989 student rebels were out of the question, but economic reform would forge ahead.

China's ruling party would not limp into extinction like Soviet bloc communists. It would let you become a billionaire, but not a dissident. It would not be mocked, and would keep its iron grip on power.

SECRET STATE

Vital to preserving that grip amid tumultuous social change is a huge and vigilant secret state, at whose heart is the State Security Bureau -- a shadowy political police force.

My experience on June 4, 1989, lifted a corner of the veil on that world. It was by turns terrifying, surreal and ludicrous.

After midnight I was in a crowd on Beijing's East-West boulevard, just off Tiananmen Square, watching a troop column march toward the heart of the doomed democracy uprising.

The front rank fired straight at us. Some fell.

After joining a panicky stampede, I set off in search of a phone. Suddenly the streets were deserted. I'd forgotten that on my route stood what was said to be a State Security base.

Half a dozen plain clothes men ran out. They began by dragging me over a railing, skinning my knees, then frogmarched me into the base past a wall slogan: Serve the People.

They bundled me into the back seat of a crowded land cruiser that hurtled off into the night. My pockets were emptied. Give him the 'apron', someone said. It was a blindfold -- but, for a European big-nose, it was easy to peep out under it.

I complained. Under the constitution, you have to identify yourself when making an arrest, and not use unnecessary viol--.

My escorts responded by slapping me over the head for a while. A man in the front turned, stuck a pistol up my nostril, and uttered the Chinese for: One move and you're dead.

A knife sliced off every shirtbutton, right through the cloth. Years would pass before I understood why.

Things went downhill. The vehicle plowed into a crowd, who guessed it was a secret police car. There were angry shouts of They've got a prisoner! and, I think, from my view under the blindfold, someone out there brandishing a petrol bomb.

Oh no, I thought, the mob's going to set fire to the car and, pinioned blind in the middle, I'll be last one out. Or rather, the last one left in. I'm only 28 and it's all over because of a pro-democracy pyromaniac. And Reuters owes me annual leave.

The pistol man opened his window and fired coolly into the crowd, which scattered. Elsewhere, some security men were lynched that night by mobs incensed at the killing of hundreds of unarmed protesters; perhaps the pistol man had saved us.

TEA BUT NO SYMPATHY

Then, in a bewildering sceneshift, I was led out of the car, gently pressed into a velvet armchair, allowed to remove the blindfold and offered a cup of tea.

A dozen men sat around a huge mahogany table. Most of my belongings were returned, including a handful of buttons.

You broke martial law by being in central Beijing, said one. Who is Chen? He had found the one legible word in my notebook. The rest was a spaghetti of shorthand, which I knew they couldn't decipher, because half the time even I couldn't.

Someone in the crowds today, I said. That was hardly a betrayal, as there are half a million Chens in Beijing.

Just when I thought I might be allowed to go home, there was another sceneshift. Blindfolded again, I was back in the car. Dawn cracked as we raced through a gate topped with a red star.

Then I was in a windowless concrete basement. A breakfast was thrown in -- rancid milk, stale bread and luminous sausage.

A man in a suit turned up. You broke martial law. Write a self-criticism admitting it. He handed me pen and paper.

If I do, can I go home? I asked. He didn't say no.

Left alone, I wrote a contorted self-exculpation, suggesting I may have inadvertently broken the law but repeating my important commentary on the Chinese constitution.

He took it away for translation, returning hours later. This won't do! You haven't admitted anything! he frothed.

A new draft was rejected. After much haggling, the script read: I broke martial law. Not a stand of great heroism.

Then I was pushed out of a van into an alley and shambled, near-delirious with fatigue, to a road.

I could hear gunfire, and smoke billowed over the rooftops. I didn't know where I was, and not another soul was on the street.

TAXI DRIVER

A tiny Fiat trundled toward me. I flagged it down.

Are you a taxi? Yes, get in. The Reuters office was miles away, past trigger-happy army units, but this insane cabbie didn't care. He even gave me cigarettes, and expressed sympathy over the holes in my shirt and blood on my jeans.

Pathetically grateful, I blurted out what had happened.

But they must have had a reason to detain you, he said. Perhaps you know some of those student leaders, do you? Or some foreign spies? Do you know them? I said I didn't.

He took me home for four times the usual fare. As I got out of the taxi -- no meter, no sign -- I realized he was a cop.

My 14-hour incarceration was revealing: even amid deep crisis, with bullets flying in the capital, the secret police had the resources to waste many man-hours on a minor detainee.

And who would guess they sometimes drive suspects home, or that in hacking off buttons, they honor an ancient tradition?

Years after June 4, I flicked through a book of Ming Dynasty prints. One showed a man being chased by a crowd, who know he's an escaped prisoner because his shirt, its front fastenings torn off, is flapping open to expose his torso.

China