IT WAS 3am when the telephone rang. Before I had lifted the receiver, I knew that the next 24 hours would be testing, stressful and possibly dangerous, that I was to spend about pounds 1,000 of someone else's money and travel at least as many miles. I might have to lie in order to get my way, step on a few toes, break a few rules. I picked up the telephone.

The man at the other end of the line made no attempt to apologise for the unforgivable hour of the call. He did not even ask for me by name. In an authoritative yet hopeful tone, he spluttered: 'Istanbul - 0700 hours, return tomorrow, cab'll pick you up at 0500; pounds 120 expenses, OK?'

It was the small, busy courier company based in Baker Street that has been sending me off on these little missions for nearly four years. In return, I receive the airline ticket and an agreed amount of cash for my hotel, food and additional travel expenses. My primary task is to deliver my consignment as quickly and safely as possible while spending as little money as I can in order to keep the change.

Most OBC (on-board courier) jobs are for media, film, design and advertising-related industries, although I have delivered everything from replacement credit cards to a three-piece suit for a mega pop star in California.

Arriving at the airport a couple of hours later, I pushed the queue at sales and reservations, then at security, claiming falsely that my flight was about to depart. Queue pushing is to an on-board courier what the shoulder barge is to a professional footballer; it is not pretty, but highly effective. I am an on-board courier and I am not paid to stand in queues, I am paid to push them.

For this particular job I had been given nearly four hours' notice and a cab to the airport. Few jobs start as luxuriously as this; normally my pager will bleep, I'll leap from the table and grab the nearest telephone. 'Office] Now]' commands the voice at the other end of the line. Obediently, I will drop everything and head for the office, where I am given my consignment and relevant information, then sent off down the tedious Piccadilly Line with only an hour to make my plane.

As I boarded the aircraft, a three-hour flight ahead of me, I snapped up a newspaper from behind the stewardess, who reminded me in a condescending manner that 'Newspapers are only for club class passengers, Sir.'

In the early days I had managed to upgrade myself into club class free of charge on nearly every flight. I would have in my possession a blue club class boarding pass left over from a job to Tel Aviv, which I would casually allow to stick out of the top of my Filofax. I would always make sure I was the last passenger to board the aircraft and would head straight for 'my' seat, exuding the curt, somewhat aloof manner of an executive with a lot on his mind. I would then hide behind a large newspaper and hope no one would notice.

I had managed to get away with about 20 upgrades before they caught me quivering behind my copy of the Independent. Showing the stewardess my real boarding pass, I managed to 'oops' my way back into economy class without any serious recrimination.

Successfully through Turkish customs, I dashed into town by taxi to deliver on time. When I arrived at Zuhurat Baba, a bustling side street in the centre of Istanbul, the consignee was nowhere to be found. I waited for half an hour, then telephoned London so they would not start to panic. Two hours later I was still sitting in the sun, nipping across the road for small doses of Turkish tea. The lack of sleep had started to get the better of me, and the sun and tea acted as an adequate life- support system.

When he finally arrived, Aydim Yasar was a touch more hospitable than your average recipient. Once I had telephoned London with confirmation of delivery, he insisted on telephoning his mother to ask if I could stay the night at their home. On a tight budget and in a city where I knew no one, this was a small miracle.

My experience of accommodation as an OBC has ranged from a stone bench in the waiting room at Padova railway station to an invitation by an extremely attractive blonde into her chalet at Courchevel. I have slept in airports, office doorways, beaches and parks, but usually end up in a cheap hotel or youth hostel, always aware of the agreed expenses and that the less I spend the more I keep.

Mrs Yasar's was a little like a respectable second-generation Italian New York apartment I had once visited. Tasteless yet comfortable furniture surrounded the most important item in the living room, a large wooden-surround television, which was puking out a stream of Turkish game shows.

I sat down and savoured the experience, caressing the sky-blue sofa, visually lapping up the extremely flirtatious game show hostess, whose sexuality was oozing into the room. After a couple of glasses of tea, Aydim and I left Mrs Y to her game shows and went into the kitchen to eat the very nice sheep's intestines that Mrs Y had prepared earlier. I arose at dawn to catch my 7am flight, thanked Aydim again and took a taxi to the airport.

On arrival in London, I phoned the office to let them know I was back on my pager and available. 'Paris]' squawked the voice at the other end of the line. 'Get your arse down to Terminal Four. You'll be back this evening, pounds 75, OK?'