After Mervyn Jackson's adoptive parents died, he became curious about his roots and decided to try to trace his birth mother, a quest that took him across the world. But the 54-year-old from Derby did not find his voyage of discovery all plain sailing.

When my parents informed me that I was adopted I took it in my stride, as any three-year-old would.

They later explained that my other parents had gone to live in Persia and could not take me with them. I sometimes wondered why they left me behind but it didn't really bother me; I had a very happy childhood.

As I grew older I became more curious about my other family but any inclination I might have had to try to contact them was stifled, partly through loyalty to Mum and Dad and there was the added difficulty of a needle in a Persian haystack.

By the early 70s Mum and Dad had passed on. Freedom of information made it possible to obtain one's original birth certificate and I had a sudden urge to find my roots.

Knowing my name at birth made it quite easy to get that certificate but I held it as though it were a big cheque from Littlewoods. My mother's name was Doreen and I soon discovered the real reason for my adoption; her husband was not my father.

This did not come as a major surprise; from my teenage years onwards I never believed that story about Persia.

The local history library in Derby was the next port of call, where I soon had my enthusiasm dampened. The people who lived at the address given on my birth certificate had a Polish name.

Despite this I went to the address, on Osmaston Park Road, and walked nervously down the path next door. The woman who answered looked puzzled as I explained that I was a relative of her old neighbour.

She shook her head, saying she had lived there since the 30s and nobody of that Polish name ever lived in the vicinity, nor did Doreen.

I could not believe that my mother was able to lie about her address on an official document, and how could the library get it wrong about the Polish people?

A few days later I received a phone call from a lady with a familiar Polish name. She confirmed my date of birth and explained that she was my mother's cousin.

She once lived on Osmaston Park Road, next door to the woman who would not divulge any information to a stranger but who had quietly taken note of my name and the fact that I lived in Duffield.

The following day found me meeting a blood relative for the first time, listening to the story of my distraught mother moving from Leicestershire to Derby to have an unwanted baby. And how her cousin met the Jacksons, like ships in the night, and handed me over, then disappeared forever - almost.

She apologised for not keeping me herself, but she wanted to raise a family of her own. I told her not to worry, I'd been all right.

It was a thrill to look through the many photographs of my mother, just to see her face at last. I discovered that my natural father died in the early 50s and that Doreen and her husband really did go to Persia, or Iran as it is today.

They moved to South Africa, where they had settled into retirement. They had a son, David, who was three years older than myself. He lived in England and, sadly, was suffering with MS.

Their younger daughter, Mary, lived near them in South Africa. Before I could ask, my new aunt made it clear that "South Africa" was as specific as she would be. David and Mary were never informed about me and it was crucial that I did nothing to shatter their ignorance.

I was put in contact with one of Doreen's sisters, who was charming and promised to let me know when Doreen next visited England. No hint of an address, of course.

Several years passed and it transpired that Doreen and Mary had been to England a couple of times. Excuses were offered about not having the opportunity to meet me but it was obvious that Doreen did not really want to make contact.

In 1990, we received an invitation to visit an old friend who had emigrated to South Africa in the 70s. My wife, Liz and I had seen little of John and his South African family in all that time and we jumped at the chance.

We flew to Johannesburg the following year and after a cursory look around John's place, I made a beeline for the telephone directory. There were five possibilities, five numbers that may get me speaking to my mother.

Within a couple of days we were flying again, John having acquired a package that would take us to Kimberley, Cape Town and Durban.

At our hotel in Cape Town I perused the local directory and discovered three more names, one of which could belong to my mother. I had to start somewhere so I made up my mind to give it a whirl.

I said to Liz: "What if a man answers? It would be better if a woman were making enquiries about his wife."

She didn't agree, saying that I was just too scared to go through with it.

Without further ado I was on the phone, selecting the address nearest our hotel. A man answered. I asked if I could speak to Doreen and, instead of saying: "Doreen who?" he said, "She's out, she's at our daughter's."

I could not believe my ears. I explained that I was a friend from England and, incredibly, he obliged me with their daughter's number.

"I've hit the jackpot!" I yelled to Liz, which brought tears to her eyes, as she encouraged me to get dialling.

Liz pointed out later that my legs were visibly shaking. The purring telephone could have been on a Hitchcock film, the way it set my chest pounding; I can't remember ever feeling so nervous. A woman answered. I asked to speak to Doreen and she said: "Speaking."

Unless there had been a terrible coincidence, my mother was on the line. At first my voice was in empathy with my legs and I could barely talk.

With trembling vocal chords I told her my name and asked if she knew who I was. She did.

There followed some gibberish on my part and short answers from her; it became apparent that she could not say too much, being within her daughter's earshot.

I told her where we were staying and she agreed to meet us. For the remainder of that day I was in some kind of trance, taking a memorable drive up Table Mountain and being more concerned about my mother.

The following day brought fears of another disappointment; I didn't think Doreen would turn up but, right on time, there she was at the hotel reception.

I will treasure that magic morning, taking tea with my wife and my mother in such a glorious setting. It was not an emotional reunion, we were strangers after all, but it was a delightful excursion into each other's life history.

We agreed to write and some months later I was to receive my first birthday card from my first mother.

Doreen made it clear that her husband had been willing to stay with her after I came along but he could not allow her to keep me. He also insisted that the family should never let on to David nor, when she arrived on the scene, to Mary.

Doreen and I corresponded for a number of years until, one day I received a letter stating that she wanted me to stop writing. Her husband had passed on by then and I believed that would be the signal for her to tell Mary about me. The opposite was true.

Having kept quiet all those years, Doreen found it impossible to admit her story to Mary, afraid of the reaction. I was most upset that I would never see her again and that Mary would never know about me.

For 12 months I stewed on the subject, until I had to put my thoughts on paper. It was not easy writing a critical letter to an elderly lady but she had to know my feelings.

Shortly after receiving my letter, Doreen had a horrific accident near her home in Cape Town, when a car ran into her, sending her through its windscreen. She was in hospital for a long time, very lucky to escape with her life.

Mary decided to get her mum into a home when she came out of hospital. Whilst clearing everything out of her flat, Mary came across that final letter from me, along with the first draft of Doreen's response.

Had she found any of my previous letters, which were of the bland, chatty type, she may not have given them a second thought but here was a disapproving letter, making reference to rejection and to a half-sister who may want to know about her brother.

Mary was bewildered and got on the phone to her aunts in England but they denied any knowledge - having been sworn to secrecy back in the 40s. She had planned a visit to England with one of her daughters later that year and Mary arrived at her aunt's armed with my letter.

She demanded to know who I was, saying that if no one would tell her, she would contact me anyway.

In June 1997, I received a call from an aunt in Leicestershire, asking if I would like to meet Mary. That weekend I was introduced to my sister, my niece and several other relatives, who welcomed me into the family.

Over the next couple of weeks Mary and I met up several times. She was thrilled, albeit baffled that everyone managed to keep my existence secret, especially when they were such a gossipy family!

She explained that she and David never kept secrets and she would have to tell him about me. I was not too keen on the idea because he was so ill and I could not imagine that he would welcome me the way she had.

David was not too impressed but agreed to meet me. Our one and only meeting was a little uncomfortable and I am still not sure it was a good idea. David died last year, having suffered MS for 27 years.

Mary's younger daughter said poignantly: "Well, Mum, you have lost one brother but at least you have found another."

In an ironic twist of events, Mary took several months to pluck up the courage to talk to her mum about me. Doreen became increasingly incoherent after the accident but Mary was afraid that if she did understand, the shock would be too much for her.

Mary need not have worried; when at last she mentioned my name, she could have been talking about the weather, for all the impact it made.

Liz and I went to Cape Town to meet the rest of Mary's family and when we visited Doreen, we asked if she could remember who I was. She said: "I think so," but her conversation was scrambled, as she related discussions she had just been having with people who were long gone from this planet.

Since our visit, Doreen's health has worsened and she does not look like recovering. Doreen must have suffered a great deal over the years, having to keep such a secret, and it is sad that she never knew how happy Mary would be when the skeleton came out of the cupboard.

If Doreen had not had the accident, she would have replied to my final letter then destroyed it, as she did all the others. I probably wouldn't have met Mary. Yet Liz and I now look forward to the next visit from South African relatives and to our return to the "Cape Of Very Good Hope".