For 40 years, hundreds of women fought for justice after taking a pregnancy-test drug in the 1950s and 60s that they say killed or led to severe foetal abnormalities in their children.

Less well known were the warnings of Jewish paediatrician Isabel Gal, who was then working at Queen Mary’s Hospital in Carshalton and who was the first to raise concerns about the hormone-based drug, Primodos.

A new documentary made by Sky News shines a light on the attempts by Gal to blow the whistle on Primodos — and how her efforts were not only ignored but damaged her own career.

Ms Gal, a Hungarian Auschwitz-survivor who came to Britain following the failed Hungarian Revolution of 1956, had her warnings ignored and was, in claims made by her daughter Kathy Gal, “blacklisted” because of her concerns — while the drug remained on the market.

Primodos was manufactured by German pharmaceuticals firm Schering and was given to more than a million women between 1959 and 1978. The Sky News investigation alleges that it was initially placed on the market without adequate testing having been performed.

The documentary, which is fronted by Sky News’ Home Editor Jason Farrell, will be broadcast on Sky Documentaries on Monday and hears the heartwrenching testimonies of mothers and children allegedly affected by Primodos.

It also follows the subsequent legal battles and the campaign for justice waged by the Association for Children Damaged by Hormone Pregnancy Tests, an organisation created by former users of the drug.

Isabel Gal first suggested the link between foetal abnormalities and Primodos in 1967, in a letter submitted to prestigious scientific journal Nature, and raised her concerns with drugs regulator William Inman.

However, it took a further 11 years for Primodos to be taken off the market as Ms Gal’s concerns were not taken seriously.

After a failed legal challenge against Schering in the early 1980s, the campaign for justice had new life breathed into it as children that claimed to have suffered the drug’s effects began to ask questions.

The campaign by the Association for Children Damaged by Hormone Pregnancy Tests — which was created by one of the survivors — ultimately led to the issuance of a formal apology by the Health Secretary Matt Hancock for the regulatory failures over Primodos following the completion of an independent review led by Baroness Cumberlege.

Speaking to the JC, Ms Gal’s daughter Kathy — who appears in the documentary — says that she believed that the developments in the case are a “partial vindication” of her mother’s work.

“It has taken an unbelievably long period of time and unbelievable pressure and work from the people involved and affected in continuing to press for it,” she says.

“She was incredible tenacious and full of integrity,” Ms Gal continues. “She found something that she thought needed investigation and wouldn’t give up, particularly when the issues with it became more and more clear. She just wouldn’t give up.”

Isabel Gal’s career stalled as soon as she raised concerns with the regulator over Primodos, and Sky’s investigation claims that the regulator William Inman failed in his role due to an overly cosy relationship with Schering.

“She was blacklisted,” claims Kathy Gal. “She was blocked from getting any other senior positions. They just effectively stopped her from working. It is terrible, absolutely appalling.”

Sky’s search through the archives of Primodos suggests that machinations within the medical world were intended to silence Ms Gal, revealing: “One of the positions that she had been offered was withdrawn. She never had the opportunity to complete the research that she felt was so badly needed.”

Ms Gal, who is described in the documentary as a “bit of an outsider,” was an Auschwitz survivor and had gone on to practise medicine in Hungary after the war.

She qualified from the University of Budapest’s medical school and began working as a paediatrician in the Hungarian capital. In 1953, she married Endre Gal, a mathematician who went on to teach at Imperial College in London.

During the Hungarian Revolution in 1956, when thousands of Hungarians fled across the Iron Curtain into Austria, Ms Gal and her husband came to the UK, where an aunt had settled after the Second World War and retrained at university in Scotland.

Kathy Gal suggests that the sidelining of her research and warnings during the Primodos scandal may have been related to a perception of ‘foreignness’.

“I don’t know,” she said, “but none of the motives for her being stopped from working were good. A small – and actually irrelevant – part of it was because of her ‘foreigness’. She never lost her Hungarian accent and never sounded English and this was an insult that was implied or thrown at her more than once,” Ms Gal recalls.

Kathy Gal says that she is “proud beyond belief” of her mother, who died in 2017, and her work in raising concern over Primodos, adding that her past put other concerns into perspective.

“We talk about having to stay in during the pandemic,” she said, “I know that this is a very terrible and extraordinary time.

“But when I think back on what my mother and father, and my family, went through, and the kind of people that they were when they came to England and re-established themselves, that change and uncertainty that came with it were enormous and extraordinary.How do you do that and still be incredible people, and not dwell on the past? I am beyond proud.”

In 2006, Bayer acquired Schering, and the company is now facing a multi-million-pound lawsuit launched by the alleged victims of the drug.

The Sky News documentary, ‘Bitter Pill: Primodos’ airs on Monday, August 24 at 9pm on Sky Documentaries and on NOW TV