A man investigating his family history through DNA testing has uncovered a long-held family secret: his mother was the sister of Ronnie Biggs, one of the most notorious figures involved in the 1963 Great Train Robbery. Ian Dowding, 77, learned of the connection when his son, Alex, sent him DNA ancestry results.

Biggs, who played a role in the heist and later gained infamy for his escape from prison and life on the run in Brazil, was one of 15 individuals involved in the robbery. The gang made off with £2.61 million in cash, an amount now considered to be over £50 million. The crime took place on August 21, 1963, when the crew stopped a Post Office train near Ledburn, Buckinghamshire.

Dowding stated that while he knew his mother, Iris Dowding (née Biggs), shared a surname with the infamous robber, she had always dismissed it as a coincidence. He recalled his father making a single joke about it over dinner, but the subject was never discussed further. Iris had told her children she had two brothers, Jack and Victor, but never mentioned a third brother named Ronnie.

"When the results came it was probably the same as most males in this country, a bit of Irish, Swedish, nothing exotic," Ian Dowding recounted of the initial DNA findings. "But then he came across something else."

Alex's research revealed that Ian's great-grandparents were Henry Jack Biggs and Lilian Edna Biggs. Ian had jokingly added to his son that there was "no relation to Ronnie," only for Alex to message back with a surprising revelation: "I think she had four brothers," and then, "one of the brothers were called Ronnie."

Ian's mother Iris Dowding, nee Biggs (pictured) had never revealed to her children that Great Train Robber Ronnie Biggs was her brother

Biggs was arrested on September 4, 1963, and served 13 months at HMP Wandsworth before his daring escape on July 8, 1965. He evaded capture for nearly four decades, living in Australia and Brazil before voluntarily returning to the UK in 2001 to serve the remainder of his sentence. He died in 2013.

Dowding expressed his astonishment but not distress at the revelation. "I was flabbergasted but not upset or horrified in any way," he said. "In fact I thought it was incredibly interesting and amusing, and I had no feelings that 'oh God, I come from a criminal family' or anything like that."

He speculated that his mother's anxiety and her decision to sever ties with her family stemmed from a desire to distance herself from her notorious brother and his criminal past. "She must have thought it was shameful to be associated with such a criminal," Dowding reflected. "My mother was always very anxious, we weren't allowed to have a telephone in the house, she wouldn't have anyone over. It makes more sense now."