FOR a long time, John De St. Jorre had a vague memory of his mother who was never there.

Not knowing any different, he and younger brother Maurice would tell school friends she had died in the Second World War.

"When I was four, that was it. My father took us away," he said.

"Nobody ever talked about her and there were no signs she ever existed, no memorabilia, nothing like it.

"Unlike my brother I had a memory of a young woman who I was convinced was my mother.

"It stuck with me."

The former Colchester Royal Grammar School pupil, turned MI6 recruit, turned Observer journalist has turned his heart wrenching search to find his missing mum who appeared to vanish without trace into a novel called Darling Baby Mine.

Aged just four in 1940, father George took the two boys away and they began living in various outposts around London until he met his new wife Edith, and the family moved to Singapore.

Dismayed at the state of the school system, Mr De St. Jorre was sent to Colchester to boarding school between 1950 and 1954.

He said: "My father was a travelling salesman so not only did we not have a mother, because of the time he spent away we virtually had no father either.

"Edith saved our family and a lot of people thought she was my mother - we called her mum.

"But I never forgot, somewhere in the back of my mind there was this image of this other woman but to everyone else it was as if she didn't exist."

Leaving the grammar school with very good grades, Mr De St. Jorre found himself accepted into Oxford University, via a spell of National Service.

Whilst there he was recruited by MI6 aged 24 when he found out the smallest detail about the long lost family member when an application form forced his father to open up small details.

He said: "I had to answer questions about my mother's relationship with my father, whether they were divorced, things like that.

"It was the first time we ever talked about her.

"I got her name then.

"Grace."

In 1965, George died and Mr De St. Jorre's search for his mother began in earnest.

"I never forgot my mother but I still had such love for my father," he said.

"When he died I felt liberated and ready to find her."

After four years of paper trails in a world without the internet, having his path blocked by stuffy senior civil servants in grey suits and life-changing coincidences he found she had been placed in a mental hospital after initially suffering with something which was probably originally close ot Post Natal Depression.

He said: "I think it began after the birth of my brother.

"If it happened now there would be people to talk to, counselling and people to visit her - I have talked to sufferers who tell me it is beatable.

"But she was just put into this hospital with people who were dangerous, and she became that way herself.

"She was subject to all sorts of horrible treatments like electric shocks and frontal lobotomy.

"When I found her I went through her sister Olive, an aunt I never knew I had, who then became part of my family.

"She was marvellous and helped me visit my mother.

"The pictures I had of her she was a beautiful woman -vivacious- and she did not look that by the time I met her again.

"You could see the damage 40 years in institutions had done to her."

Grace lived for four years after the reunion, and the pair would meet again on a few occasions and she even penned her long lost son a letter proclaiming him her Darling Baby Mine.

Sadly Maurice, who had no memory of his mother, had no wish to meet her again.

"If I were in his shoes I probably would have reacted the same.

"He said our stepmother had become our mother.

"But for me it was different, because I had the memory."

Mr De St. Jorre, now 80, and living in Rhode Island in the USA, carved out an incredibly successful career as a journalist but says writing about his own experiences of the search and the treatment of mental health patients in the 20th century was a completely different experience.

He said: "It is a little bit odd because it is something I have lived with all of my life, but didn't start writing about until much later.

"As a journalist I am used to writing about other people and I had to write about myself and my family.

"Because of the way it happened it reads like a detective novel and I create scenes and invent a bit of dialogue so it is not just a memoir."

Darling Baby Mine: A son's extraordinary search for his mother is widely available at book shops and on Amazon.