An exclusive documentary made by Sky News due to air on Tuesday night on Sky Atlantic will reveal how documents were destroyed and information withheld about a drug that may have deformed and killed babies in the womb. Jason Farrell has the story behind the investigation.
When Marie Lyon suspected she was pregnant with her first child 47 years ago, she didn't think to question the GP who told her to take two tablets, explaining they would tell her if she was indeed carrying a baby.
She was given two small round pills in a green packet, and advised to take one. If she didn't have a period, she was to take a second 12 hours later.
"The guilt I felt later because I didn't question it was unbearable," says Marie.
When her daughter Sarah was born, it was clear from the way the nurses rushed her away immediately that something was wrong.
"When they brought her back, she was swaddled up to her neck in a blanket. They just said: 'Look, we're really sorry but we have to tell you that your daughter's arm didn't form from below the elbow.'
"When they did unwrap her, she was beautiful, but just where the elbow had been there was this perfect, tiny little palm with four little fingers and a thumb."
Marie was one of 1.5 million women in Britain who took Primodos, a German drug prescribed by GPs in the 1960s and 70s, in the early stages of pregnancy.
She believes that the tablets she swallowed on the advice of her doctor stunted Sarah's development in the womb.
But Sarah was in many ways incredibly lucky. A huge number of alleged victims were left appallingly damaged.
According to research carried out at the time, a number of women given the drug suffered instant miscarriages, thousands more gave birth to babies with missing limbs, abnormalities in their internal organs, brain damage and heart defects.
Many of these children died before reaching adulthood; of those still alive, some are deaf, dumb and blind.
It is now known that one dose of Primodos contained super-strength hormones that, later, would be used in the morning-after pill.
They were essentially a powerful oral contraceptive, made up of 10mg of norethisterone and 0.2mg of ethinylestradiol.
If a woman was pregnant, these large doses of progesterone would, it was thought, simply be absorbed into the body. If she wasn't, they would trigger menstruation.
But the concentration was extremely high in today's terms, one dose of Primodos equates to 13 morning-after pills or 40 oral contraceptive pills.
Marie had no idea what had caused the malformation of Sarah's arm until a phone call when her little girl was eight years old, which shed some light on what may have happened.
"It would seem the association set up by some of the victims had accessed records from the health authorities to find children who had been born with disabilities. That was where they found my details.
"The woman on the phone asked me if I had taken any tablets during my pregnancy. When I told her about the two pregnancy test tablets I had taken, she said: 'Have you any idea what's in them?'
"I couldn't take it in. I was thinking: 'She's just told me that I've taken two tablets that are 40 times the strength of an oral contraceptive.' I just felt pure anger."
I have been following this story for many years, striving to find the truth behind a what looks like a terrible injustice which much like the Thalidomide scandal seems to have been covered up at every turn.
My investigation, which will be laid bare in a Sky Atlantic documentary on Tuesday, began in a loft in Liverpool six years ago when a man called Karl Murphy emailed me about a discovery.
He'd been up to his mum's attic and found four suitcases full of documents about pills she had taken as a pregnancy test. Karl, now 44, was born with shrivelled hands and feet.
His mum, Pam, had been part of a campaign group that attempted to prove that Primodos had harmed their babies.
Karl's files showed that, in June 1975, a warning had been placed on Primodos packets by the UK regulators.
It stated that the drug should not be taken during pregnancy because of the risk that it may cause malformations. At this stage, it had already been on the market for 15 years.
Two years later, regulators wrote to doctors stating: "The association is confirmed."
This compounded evidence that had been discovered 10 years earlier, in 1967, by a paediatrician called Isabel Gal, had observed a worrying pattern in babies born with spinal defects.
Her research found that a high proportion of those with spina bifida came from mothers who had taken hormonal pregnancy tests.
I met up with Dr Gal in 2011. Then in her late 80s, she told me she had fought a 10-year battle to get the drug removed from the market, but had been stonewalled by every institution, from the Department of Health to the Committee on Safety of Medicines.
I then spoke to a statistician called Norman Dean who had conducted a study in 1968 which showed that the incidence of birth malformations in the UK rose in tandem with sales of the drug.
He told me he had recommended to the German manufacturer, Schering, that it conduct further studies, which he believes were not carried out.
Given the evidence, you might presume mothers who used this drug would have strong chance of claiming for compensation against Schering.
But that hasn't been the case. In 1982, an attempt to bring the case to court by the alleged victims fell through and legal aid was withdrawn from the 700 families who were battling to be heard.
It was deemed that they would be unlikely to prove a causal link between the drug and the malformations suffered by their children.
Marie, who is current chair of the Association for Children Damaged by Hormone Pregnancy Tests, recalls: "We were told if we wanted to proceed with the case we would have to remortgage our homes. It was as stark as that."
Our breakthrough finally came last year when we discovered hundreds of files about Primodos, had been stored unseen in the Berlin National Archives for decades.
They showed that, in January 1975, a Dr William Inman, principal medical officer for the UK government, had found that women who took a hormone pregnancy test "had a five-to-one risk of giving birth to a child with malformations".
Dr Inman spoke to Schering, but explained he'd made contact so that the manufacturer could "take measures to avoid medico-legal problems"; he doesn't tell it to recall the drug, and it doesn't.
A later document explains that Dr Inman destroyed the materials on which his findings were based, "to prevent individual claims being based on his material".
When we put this to the current drugs regulator, it told us that the decision was taken to inform the manufacturer of preliminary findings, so the company could decide whether to remove it - a rather lame reaction, by the very body that was put in place to protect the public in the wake of the Thalidomide scandal.
Schering is now owned by pharmaceutical giant Bayer, which insists that Primodos was on the market in the UK "in compliance with prevailing laws".
It says the view at the time and, after a full review, today is that "evidence for a causal association between the use of hormonal pregnancy tests and an increased incidence of congenital malformations was extremely weak".
It "rejects any suggestion" that anything has been concealed by Schering, other than privileged documents.
There is much more that we reveal in our investigation. For me the heart stopping moment came when my producer, Liz Lane, tracked down someone we had spent months searching for.
We discovered that in America there was a mother and child who had won a multimillion-dollar claim against the manufacturer of a hormone pregnancy test and embarked on a mission to find the family and learn more about this drug and its links to Primodos.
I will forever remember the first phone call that finally got through to the woman we were seeking. "I was about to get rid of this phone," she said.
She never usually used it. "I'm so, so pleased you didn't," I told her. When we finally met Ellen, her story was both inspirational and heartbreaking - a one-woman fight against the big guys.
I won't give the full story away, only to say that a delegation of Germans were sent to listen in on her case.
:: Sky News' hour-long documentary Primodos: The Secret Drug Scandal will be presented by senior political correspondent Jason Farrell, who has been investigating it for six years. It can be seen on Tuesday 21 March at 8pm on Sky Atlantic and on Wednesday 22 March at 9pm on Sky News.