'My father was notorious politician Lord Bob Boothby'

When Eliza Harrison was organising the London launch of her memoir, In Search of Truth, she contacted the journalist Polly Toynbee, with whom she went to school, to ask if she’d like to come.

She also happened to mention that her real father was not Dick David, as she’d always thought, but the colourful – and highly controversial – MP Lord Bob Boothby. To her astonishment, she already knew.

“That really shocked me,” says Eliza, 75, who lives in Sedbergh. “Still the revelations are going on. His whole family knew that (my sister) Teresa and I were his children. My mother told her mother. Everybody knew apart from Teresa and me, so it seems.”

The memoir follows a previous account of Eliza’s life, In Search of Freedom, which was published in 1997, prior to the discovery. A lifelong exponent of meditation, it led her, 25 years ago, to establish the Meditation Centre in Dent. “Although it wasn’t intended, it brought so many people to meditate,” she says. “I taught there for 15 years and it just drew people from all over the world. Its idea was to bring together people from all different faiths and beliefs, and the underlying principle is that we’re all on the same journey.”

She uncovered her true paternity following a painstaking quest. “I remember pacing around the kitchen saying, ‘Who am I?’” says Eliza. “I had no idea for several weeks, then the pieces of the jigsaw puzzle began to fall into place. I have huge compassion for all those people who have no idea who their father is and don’t have the means to find out. Obviously because of Bob’s heritage, there’s a huge ancestral lineage there that I was able to get into. Now I just feel very warmly embraced by them all.”

Eliza grew up among the Cambridge intellectual elite with Teresa and two older brothers. It was a highly privileged life, with the Rothschilds among the family’s friends, yet she was never truly happy. “It was a challenging upbringing,” she says. “There were Nobel prize winners among my parents’ friends and I think for the children of those parents it was always going to be difficult. I was not academic at all so there was no way I could even begin to enter that world. I think because my mother wanted the best for her children she pushed us and I found that very challenging. If you didn’t come up to scratch she just got very angry.”

With her mother Nora, especially, incapable of showing affection, Eliza became withdrawn. “I can never remember being taken on my mother or father’s knee and given a cuddle,” she says. “I can’t remember either of them ever playing with me. I never remember being told that I was loved.”

Victor Rothschild – a brilliant scientist who had worked for MI5 in the Second World War – and his wife Tess took her under their wing. They invited her on lavish holidays and once, Victor even sent her to Paris to buy foie gras for a dinner party. “Because Victor and Tess Rothschild definitely knew that I was not Dick David’s daughter they became very protective of me,” explains Eliza. “They included me in the family because they knew how ruthless my own mother was with me and for that I will always be grateful, even though I was always homesick. The home I longed for was always in my mind. It wasn’t reality.”

As another close friend, Lord Bob Boothby was also a source of comfort, though she felt he preferred Teresa. “I was always touched that he added me on,” says Eliza. “It was like he didn’t want me to feel left out. My sister was different from me. She was much more outgoing, gregarious, very beautiful. I never felt any of those things.”

Unfailingly generous, on one occasion, Lord Boothby promised Eliza any gift of her choosing. She asked for a puppy or a camera, and he duly bought her a Brownie Box camera and two reels of film. Yet his love life was a tangled web strewn with affairs with married women. He was also bisexual and developed a friendship with the Krays, who allegedly procured young men for him, provoking a tabloid scandal. One day, Teresa confided in Eliza that he could be her father, but the latter never suspected that he might also be hers.

“I did ask my mother about my sister and she was obviously so nervous, she just got breathless,” she says. “She did say, ‘Yes, she could be.’ That would have been her opportunity to tell the truth about me but she didn’t. I suppose when you start keeping a secret when is the right time to tell the truth?”

As a young woman craving stability, Eliza became involved with the promising young actor Martin Potter. She soon fell pregnant and the couple were married but the relationship foundered after he won the lead role in a Fellini film and started being unfaithful. “When he was honest with me about the affairs and so on, those moments were incredibly loving and touching and moving, and that’s why I kept on with the marriage,” she explains. “There was nothing really that I had to move on to.”

She did eventually leave, escaping to the Yorkshire Dales and embarking on the spiritual journey which eventually led her to Cumbria. Now a grandmother and great-grandmother, she’s happily married to her third husband and is planning to return to the Meditation Centre, which she left 10 years ago. She hopes through her memoir to change the narrative surrounding Lord Boothby. “All the good things he did as a politician and in his constituency in Scotland were set aside when the scandal broke about his relationship with the Krays,” says Eliza. “So much of his life was helping those less fortunate than himself. He also made sure that all schoolchildren after the war had free milk and that vitamins were put in bread. That was just lost amongst the Kray scandal.”

While acknowledging the wrongs that have been done to her, she bears no rancour towards the perpetrators. “I’ve embraced my mother and Bob and my stepfather Dick David in a much deeper way,” says Eliza. “I loved them for who they were and how they expressed themselves. I have huge respect for them. There’s no judgement and I just feel very fortunate to find out the truth before I died.”

In Search of Truth by Eliza Harrison, The Book Guild, £12,99, is out on May 28.