Family secrets: Effie Dicketts was raised as her mother's sister. After spells in prison, he reinvented himself as a stuntman, businessman and spy, becoming a double agent during the Second World War. His highly developed ability to fool people finally paid off for his country: he survived a five-day interrogation by the German secret service and convinced them he was a traitor. By doing so, he supplied British intelligence with key insights into enemy operations. Yet little more than a decade later, at the age of 57, he was discovered penniless and alone in a London bedsit, having apparently killed himself. Who was this extraordinary man? That's the question that Walter Dicketts' granddaughter, Carolinda Witt, has tried to answer ever since she discovered his identity in 2008, 10 days after her mother Effie died at the age of 87. Witt has written the story of the exploits of her grandfather in a book called Double Agent Celery – MI5's Crooked Hero, to be published next month. If Walter Dicketts specialised in secrets and lies, there was none more painful for Effie than going to her grave never knowing her father's name or what he had done.

Mona Vale author Carolinda Witt has written a book on the colourful life of her grandfather, Walter Dicketts. "She died just 10 days before I could have told her all this," Witt said from her Mona Vale home on Sydney's Northern Beaches. "It was a most peculiar thing. My mother was such a special, beautiful person, so kind and funny and elegant, and I had no one in her family to tell that she had gone and it deeply upset me and I thought 'I'm going to find them'." The "them" were Effie's relatives, for she had been the victim of another devastating family secret. She grew up thinking her grandmother, Euphemia, was her mother. That's because Effie's mother, Dora Viva Guerrier, a long-legged dancer with the famous Tiller Girls in London, was so ashamed at getting pregnant by Dicketts that she pleaded with her own mother to raise Effie as her own, while she pretended to be Effie's sister. The story of Dickett's exploits, Double Agent Celery – MI5's Crooked Hero, will be released in October. The secret was kept until Effie, aged 20, tried to find work but discovered she had no birth certificate and could not prove her identity. A confrontation with her "mother" led to her discovering the true identity of her "sister".

But Witt has uncovered another family secret. Also unknown to her mother, she had a brother. Dora and Dicketts had a son, Dick, who was given away soon after birth. "My mother was very ashamed of being illegitimate and she avoided answering questions about her background," Witt said. "I was 12 when we left our home in Kenya and went to Denmark to visit who I thought was my mother's sister Dora. My brother and I were wild little East African children compared to this strict Danish family and they went out for dinner and my brother and I had a pillow fight, a stupid kids' thing. "The nanny complained about our behaviour and at breakfast Dora laid into my mother, saying we were wild and ill-disciplined. My brother, who was only about 10, tried to protect my mother and said 'you bloody aunty Dora', at which point Dora went bright red and threw us out of the house. We never saw her again. "That's when my mother confessed to us that Dora was not her sister but her mother. I now know she must have been thinking how could Dora criticise her for being a bad mother when she'd abandoned her own daughter." When Effie died in 2008, she set about trying to find other members of Dora's family.

"I wanted them to know but I had no luck. Then my daughter Holly found someone on an ancestry site searching for my mother by her real name, Guerrier, which only we in the family knew. "I called the man she found, Mike Adair, in Bangkok and he said 'are you sitting down?' Your granny and my granny were with the same man at the same time. My granny was his wife and your's was his mistress." Adair was Dicketts' grandson, from his first marriage to Phyllis Hobson, before they divorced and he married Dora. "Then Mike said: 'Did I know mum had a brother who had been given away at birth?' I felt like shouting, 'No, of course I don't.' I didn't really believe it. "So I flew to England and drove down to Wales and knocked on Dick's door. This man of 89 came to the door. He had a very erect posture from his military background. He had the same mannerisms as my mum and the same quirky humour. I had warned him that I didn't believe all this so I wanted a DNA test. He said, 'absolutely'. He had a twinkle in his eye and was smiling ear to ear and invited me to have a drink, then cooked lunch."

Dick had been told by his foster mother of his father's criminal background but he didn't know about his war record until the files were released in 2006. Since then he'd been trying to get in touch with his sister. He revealed he had been in contact with one of Dicketts' other sons, from his marriage to Vera Fudge, another Richard who had changed his surname to Tudhope. Richard Tudhope recalled his father as being very well dressed and well spoken, "looking like a movie star, a generous man with a taste for the high life and dinner at the Savoy". But his love of the high life led him down a criminal path again and in 1948, after five years on the run and about to give himself up to the police, Dicketts wrote to his second eldest son, Richard Tudhope, with some advice: "Be honest and straightforward in everything you do, and have a kind and generous heart – these are the only things that count." So, if Witt started out with a strong desire to right the injustice done to her mother, what does she feel about her grandfather now? "I feel a bit defensive about my grandfather now, which surprises me. I think in the war he genuinely tried to do the best for his country. In terms of his marital life and responsibility to his children, he was a crook, a charming crook, a gentleman crook. He wasn't going out stealing from the poor. I think it was a question of survival. He is a bit of a mystery.

"I think he was an emotional man and not some shut-off Asperger's character who could go into the middle of Germany and pretend to be a traitor. I think he did these things at great cost to him. "Even though my mother was dead, I wanted to see her restored to her rightful place within her family. I had a sense of wanting to right the wrong but once I started to meet my own family, my mother's family, things started to change. These people were all strangers but they are not now."

The Celery Files



1900 Walter Arthur Dicketts born in Wandsworth, London

1915 Skipped school at 15 to enlist in WWI

1915-17 Served in armoured cars and tanks in France, learned to fly

1918 Flying accident

1918 Joined Air Intelligence, married Phyllis Hobson

1919 Left RAF as Captain, unemployed, first son, George (later changed name to Adair), born.

1920 Daughter Effie born to Tiller Girl mistress, Dora Viva Guerrier

1921 In court for getting cash by false pretences

Third child, Rodney (later changed name to Adair), born to Phyllis.

Jailed for nine months at Old Bailey for fraud

1922 Fourth child, Eric Richard "Dick", born to Dora

1923 Dicketts moves in with Annette Benson

Pleads guilty to fraud, given "last chance" because of war record

1924 Phyllis granted divorce

1926 Jailed for fraud

1927 Joined Mexico Air Force, then left for California

1929 Back in Britain, eloped with Alma Wood, 16

1930 Jailed for fraud

1931 Marriage to Alma annulled, jailed again for fraud

1933 Married Vera Nellie Fudge

1934 Fifth child – born to Vera – Richard (later changed name to Tudhope)

1937 Went to Singapore to buy silk

1940 Living with mistress Kathleen Holdcraft

Recruited by MI5 after meetings with double agent "Snow" in London pub

1941 Meetings with German secret service in Portugal, then five-day interrogation in Germany

Debriefed by MI5, leading to jailing of "Snow"

1943 Double Cross Committee chief agrees to release Dicketts from duty

Marries fourth wife Judit Rose Kalman

1944 Sixth child – Robert – born to Judit

1949 Jailed for four years

1951 Released and runs plantation in Malaya

1957 Divorced from Judit. Dicketts found dead in Paddington lodgings