During the final years of his presidency, President Jomo Kenyatta annually celebrated his birthday with a general amnesty for an estimated 10,000 hardened criminals, which is a lot even for Kenya. It was one way of relieving congestion of the country's over-burdened prisons. As a result, Kenya was regularly engulfed in a crime wave, which rose at an alarming rate beginning the day prisoners were released.

With so many footpads, thugs and robbers on the rampage, the police and GSU (a special service unit of anti-riot police) troops quartered in the city had their work cut out rounding up the criminals again and returning them to the slammer. Like the Limuru Road, the release, round-up and re-incarceration followed a predictable roller coaster pattern.

Road blocks were thrown up on all the main highways leading into (and out of) the city. They were often seen throughout the year on the outskirts of Nairobi, but at amnesty time the authorities maintained a special vigilance. Beyond the police barrier on the Limuru Road, a short distance before a branch road to the village of Banana Hill, the robbers operated their own favourite stretch, erecting barriers on the lonely, unlit side roads using felled trees to block the way. Unwary motorists stopping to clear the obstruction were set upon, robbed and frequently injured. Another method was for the robbers to fake a breakdown, wave a passing motorist with the pretence of seeking help!

For these reasons, I was told that on no account should I stop to offer help, but to reverse if necessary and return the way I have come. It was the early 1970s and I was in Kenya to install equipment in the new Jomo Kenyatta International Airport, staying with friends near the Village of Banana Hill. The vehicle I hired was not in the best condition, but I managed to coax it along. Besides, we usually traveled in convoy in case one of us ran into trouble, mechanical or otherwise. .

One evening, following a few hours in the city with my friends, I had to drive back to the house alone. They were staying in the city to attend a late night function. The car was cantankerous as usual. It required a push start, but ticked over well enough once it got going. I ran smoothly out of the city and, with barely adequate headlights, plunged into the darkness of the Limuru Road. Somewhere between the Kisumu service station, closed for the night, and the turn-off for Banana Hill, the engine lost power. I pumped the gas furiously and cursed the machine for its contrariness.

It was at an awkward spot, at the top of a steep hill. The headlights had dimmed to nothing, which meant that on top of the engine conking out I had a flat battery. I coasted the car downhill, steered round a sharp bend in almost total darkness and, part of the way up the next rise, came to an ignominious stop as close to the steep embankment as I could. I got out of the car, wondering what to do for the best; the vehicle had died in a dangerous spot. I returned to the driver's seat and shut the door.

A sweet pungent aroma filled the warm night air. The crickets were singing in a loud unending chorus and, from a cluster of grass huts with flickering fires far away, a faint sound of pop music came floating across the valley. In the blackness of the night it was an eerie feeling to be stranded on a lonely stretch of highway infested, I'd been assured, by criminals released from the country's jails.

Hardly a minute passed before the darkness was broken by the glow of approaching headlights. Then I was caught in the glare of the approaching vehicle's headlights as it swung around the curve and came speeding up the hill. Only by a sharp maneuver did the driver avoid smashing into my rear. He came to a sudden stop with a squeal of rubber as though done on the spur of the moment. Immediately the vehicle was at a standstill, three, four, five occupants tumbled out and approached me. Their leader, the driver, a burly fellow led the pack. I was suddenly resigned to yielding without a fight; what can one do against such odds, I thought.

"You got trouble," he said.

I didn't know whether to treat that as a statement or a question.

"You can't stay here," he continued in a deep resonant voice without pause. "It's a dangerous place. We had better get you off the road. No, man! You stay in and steer."

They pushed the vehicle up the hill without difficulty and into a private driveway, where, the leader said, it would be safe for the night.

Where was I heading? Could they give me a lift? It would be a squeeze in their vehicle, but I'd be very welcome. They would accept no payment for their help because, said the driver, he was sure I'd have done as much for him. He drove me to the house, the former home of white settler coffee growers, now owned and rented out by a member of the Kenyan parliament.

When my friends returned from their evening activities they said I was out of my mind to leave my briefcase in the car. In any case, I could expect the machine to be stripped to the axle before dawn, so we'd better go back immediately and retrieve it if, indeed, it was still there.

We arrived back at the driveway about midnight, taking along for protection a watchman armed with an old gear wheel fixed at the end of a stick. The car and its contents were intact, but while we were removing my belongings two cars stopped in the driveway entrance blocking our exit. My companion had no illusions about being caught out at night and whispered a warning to prepare for a fight as the new arrivals advanced towards us. We braced ourselves to meet them, prepared to sell ourselves dearly. Then their leader spoke with a voice of authority: clear, educated, precise.

"What are you doing here, may I ask?"

Our explanation was offered and accepted. We were faced with – and in the private driveway of – the head of the GSU.

"Be my guests and leave it here overnight. No one will touch it," he said with a faint smile in the glaring beams of his vehicle's headlights.

Life is full of surprises.