Famed for comforting the nation's broken-hearted, a documentary to be broadcast tomorrow reveals that Byrne herself turned to alcohol after being forced to give up her only child for adoption during the 1950s. She finally met her daughter, Valerie McLoughlin, just 10 years before dying in a haze of dementia that doctors said was brought on by drink.

Dear Frankie, made by Mint Productions, names Hall's Pictorial Weekly star and former Irish film censor Frank Hall as Byrne's lifelong lover and father of her child. Hall only died in 1995 but, when mother and daughter were reunited in 1983, Frankie concealed from Valerie her father's true identity, instead claiming he had been killed in a car crash in New York years before.

Hall was already married when he met Frankie in the mid 1950s on Dublin's hectic social scene. Friends say the pair conducted their relationship publicly within the small scene and Frank was the love of her life.

A job at the Brazilian Embassy after school had launched Byrne onto the scene and into Hall's circle.

"They met as working colleagues and unfortunately it turned into an affair, " said her niece Barbara Stratham.

"He was a great guy and a very suitable partner in every way . . . but he wasn't available."

By her early 30s, Frankie was working at McConnell's PR but as her career prospered her private life began to unravel. Her colleague and confidante, Mildred O'Brien, says that in 1956 Frankie was hiding the fact that she had become pregnant. "She was a big person and wore flowing clothes and I know that nobody noticed. She worked up until the evening before she went into the nursing home. She showed enormous fortitude and courage and eventually gave birth to her daughter on 12 July, 1956. On the birth cert at the time, Frankie Byrne was the mother's name and the father was 'unknown'. Frankie desperately wanted to keep her baby and there was really no way any of us could see that coming about. It was a frightful decision for her and it broke her heart."

Mildred arranged for Frankie's baby to be brought to the Poor Clares orphanage in Stamullen. "It was a sad and heart-breaking journey, " she said. "Frankie and myself drove to Stamullen.

It was within four days of her giving birth and she was very emotional. When we got there, she was shown into a large ward where all the cots were and she was shown which one Valerie would have.

Every single Sunday for six months she travelled up to Stamullen. All the time she thought she would be able to keep her herself, but in those days it wasn't possible. At the six-month time, she went up and agreed to sign to let her go for adoption."

Barbara Stratham says Frankie had felt worthless from an early age after being born into a bohemian Dublin family in 1921. "She had no relationship with her parents.

Her mother gave birth to her then handed her over to the care of a maid. She always said she felt her mother was disappointed she wasn't a boy. From an early age she believed she wasn't as loved as the other children in the family."

Barbara says her aunt never got over losing her only child and sought solace in alcohol. "She went through a very bad period of post natal depression. She was prescribed valium and became addicted to it for 10 years.

When she would drink, she became very sentimental and maudlin and unhappy. There was nothing any of us could do for her. It wasn't unusual to wake up at 4am or 5am and hear these really sad Frank Sinatra songs and her sitting up with tears streaming down her face."

But while Frankie's personal life crashed, her public life soared. In 1963, she set up her own PR firm and also started the Woman's Hour show on RTE, a programme that turned her into a household name, and dominated the airwaves for over 20 years.

Shortly before Valerie got married in 1976, her adoptive mother furnished her with information on her birth mother, but until Valerie came looking for her, Frankie had vowed not to seek out her daughter. By the mid 1970s, her relationship with Frank Hall was drawing to a close and she was feeling worthless. Meanwhile, at her home, Valerie often thought about her mother. Then one day, as she was watching television, Frankie Byrne came on her screen. "I stared into the television to see if there was any resemblance and I got thinking, " she says. "Then one day I wrote to the doctor who delivered me."

In December 1983, Frankie finally, and delightedly, was reunited with her daughter but Valerie says that the woman she met was brokenhearted. "She had an image in her head of a baby and she sees this strapping 27-yearold. You have to start rethinking parameters of who you are." Amazingly, Frankie pre-empted the question of Valerie's father but protected Frank Hall by refusing to name him to her daughter.

"She said he was a journalist who was married and had a family of his own and they had a wonderful affair. And I was born and they were heart-broken and I had to be given up for adoption. She said he went to America and was killed in a car crash in 1963. Frankie and I never discussed him again." Ten years to the day that they met, Valerie saw her mother for the last time . . . in a morgue at St Vincent's Hospital.