Thousands of people in Switzerland who were forced into child labour are demanding compensation for their stolen childhoods. Since the 1850s hundreds of thousands of Swiss children were taken from their parents and sent to farms to work - a practice that continued well into the 20th Century.

David Gogniat heard a loud knock on the door. There were two policemen.

"I heard them shouting and realised something was wrong. I looked out and saw that my mother had pushed the policemen down the stairs," he says.

"She then came back in and slammed the door. The next day three policemen came. One held my mother and the other took me with them."

At the age of eight, he was in effect kidnapped and taken away to a farm. To this day he has no idea why.

For the first years of his life, he and his older brother and sisters lived alone with their mother. They were poor, but his childhood was happy until one day in 1946, when he came home from school to find his siblings had disappeared.

A year later it was his turn.

He was taken to an old farmhouse and became the farmhand. He would wake before 06:00 and worked before and after school. His day finished after 22:00. This physically imposing man in his 70s looks vulnerable as he remembers the frequent violence from the foster father. "I would almost describe him as a tyrant... I was afraid of him. He had quite a temper and would hit me for the smallest thing," Gogniat says.

Find out more Image copyright Paul Senn Watch Kavita Puri's report Switzerland: Stolen Childhoods on Our World at 11:30 GMT on Saturday 1 November and at 2230 GMT on Sunday 2 November on BBC World News. Assignment is on BBC World Service radio from Thursday.

On one occasion, when he was older, he remembers he snapped, grabbed his foster father, pushed him against the wall and was about to hit him. The man threatened him: "If you hit me, I'll have you sent to an institution." David backed off.

His siblings were living with families in the nearby village, though he rarely saw them. He missed his mother desperately. They wrote and there were occasional visits. One day his mother made an audacious attempt to get her children back. She came up with an Italian couple in a Fiat Topolino and said she was taking his siblings for a walk. David wasn't there but it was the talk of the village when he came back that night. The police brought the children back three days later.

"The fact that my mother arranged to kidnap her own children and take them back home to Bern with her just goes to show how much she was struggling against the authorities," Gogniat says. On his mother's death he made a shocking discovery. He found papers which showed she had been paying money to the foster families for the upkeep of her four children, who had been forcibly taken away from her and were working as indentured labourers.

Gogniat, his brother and two sisters were "contract children" or verdingkinder as they are known in Switzerland. The practice of using children as cheap labour on farms and in homes began in the 1850s and it continued into the second half of the 20th Century. Historian Loretta Seglias says children were taken away for "economic reasons most of the time… up until World War Two Switzerland was not a wealthy country, and a lot of the people were poor". Agriculture was not mechanised and so farms needed child labour.

Image copyright other Image caption David Gogniat with his younger sister before they were taken away from their mother

If a child became orphaned, a parent was unmarried, there was fear of neglect, or you had the misfortune to be poor, the communities would intervene. Authorities tried to find the cheapest way to look after these children, so they took them out of their families and placed them in foster families.

"They wanted to take these children out of the poor family and put them somewhere else where they could learn how to work, as through work they could support themselves as adults," says Seglias.

Dealing with the poor in this way she says was social engineering. If a parent dared to object, they could face measures themselves. "They could be put in prison or an institution where you would be made to work, so you could always put pressure on the parents."

Mostly it was farms that children were sent to, but not always. Sarah (not her real name) had been in institutions from birth, but in 1972, at the age of nine, she was sent to a home in a village, where she was expected to clean the house. She did that before and after school, and at night cleaned offices in nearby villages for her foster mother. She was beaten regularly by the mother, she says, and from the age of 11 was sexually abused by the sons at night.

This is the first time she has spoken about her story and her hands shake as she remembers. "The worst thing is that one sister, their daughter, once caught one of those boys... while I was asleep and she told the woman... [who said] that it didn't matter, I was just a slag anyway," Sarah says. A teacher and the school doctor wrote to the authorities, to express concern about her, but nothing was done.

There was no official decision to end the use of contract children. Seglias says it just naturally started to die out in the 1960s and 70s. As farming became mechanised, the need for child labour vanished. But Switzerland was changing too. Women got the vote in 1971 and attitudes towards poverty and single mothers moved on.

I found an exceptionally late case in a remote part of Switzerland. In 1979, Christian's mother was struggling. Recently divorced from a violent husband she needed support.

Image copyright other Image caption Christian with his mother

The state intervened and took her seven and eight-year-old sons to a farm many hours away by car. Christian remembers getting out of the car and watching his mother and the woman from social services driving off.

"My brother and I stood in front of the house feeling very lost and didn't know what to do… it was a strange moment, a moment you never forget," he says.

On the first day they were given overalls and perfectly fitting rubber boots, "because before the placement the woman from social services had even asked what size shoes we wore… When I think back I do believe there was an awareness that my brother and I would be made to work there."

Christian says there was work before and after school, at weekends and all year round. He remembers one incident, at a silo where cut grass was kept to make into silage. "In winter it was pretty frozen and I had to hack quite hard with the pitchfork and I was put under pressure and then this accident happened and the fork went through my toe."

He says work accidents were never reported to his mother or social services. And if the boys didn't work hard enough there were repercussions. Food was withheld as a form of punishment.

"My brother and I just went hungry at the time. When I think back there were five years during which we constantly went hungry. That's why my brother and I used to steal food," Christian says. He remembers they stole chocolate from the village shop - though he now thinks the owners knew the boys were hungry and let them take the goodies. A former teacher of Christian's at the local school says with hindsight he looked malnourished.

But Christian remembers there were also more serious consequences if he didn't work hard enough, including violence. "We were pretty much being driven to work," he says. "There were many beatings, slaps in the face, pulling of hair, tugging of ears - there was also one incident involving something like a mock castration."

Christian has no doubt why he and his brother were placed with the farmer. "I believe it was about cheap labour... we were profitable," he says. "They expanded the farm... it was five years of hard work."

Image copyright Paul Senn

Historians estimate there were hundreds of thousands such children. For one year alone in the 1930s, records show 30,000 children were placed in foster families across Switzerland.

Image copyright Ueli Hubeli They were being abused and no-one believed them Loretta Seglias, Historian

"It's hard to know precisely how many contract children there were as records were kept locally, and sometimes not at all," says Loretta Seglias. "Some children were also placed by private organisations, or their own families."

The extent to which these children were treated as commodities is demonstrated by the fact that there are cases even in the early 20th Century where they were herded into a village square and sold at public auction.

Seglias shows me some photographs. One child looks barely two - surely she couldn't be a contract child? "She could, she would be brushing floors bringing in the milk. Sometimes they came as babies on to the farms, and the bigger they grew the more work they would do," Seglias says.

In her studies, and speaking to former contract children she finds recurring themes. The lack of information comes up again and again.

"Children didn't know what was happening to them, why they were taken away, why they couldn't go home, see their parents, why they were being abused and no-one believed them," she says.

"The other thing is the lack of love. Being in a family where you are not part of the family, you are just there for working." And it left a devastating mark for the rest of the children's lives. Some have huge psychological problems, difficulties with getting involved with others and their own families. For others it was too much to bear. Some committed suicide after such a childhood.

Social workers did make visits. David Gogniat says his family had no telephone, so when a social worker called a house in the village to announce that she was coming, a white sheet was hung out of a window as a warning to the foster family. On the day of this annual visit David didn't have to work, and was allowed to have lunch with the family at the table. "That was the only time I was treated as a member of the family… She sat at the table with us and when she asked a question I was too scared to say anything, because I knew if I did the foster family would beat me."

Image caption David with his foster family and another unidentified boy

Sarah too remembers that visits were announced and that social workers were always welcomed with cake, biscuits and coffee. "I used to sit at the table too. It was always lovely, ironically speaking, but at least I knew I was being left in peace, that nothing was going to happen." She never spoke alone to a social worker during her stay with the family.

Christian doesn't remember seeing a social worker alone either. In his documents, social workers wrote that he was "happy". In one of the letters, a visit is announced, saying it doesn't matter if the children are at school. Christian shows me letters written by his mother, detailing her concern that they were being beaten, were malnourished, and doing agricultural labour. His mother organised a medical assessment, on one of his rare visits home, and the doctor's conclusion was that he was psychologically and physically exhausted. This triggered his removal from the farm in 1985, when he was 14. His older brother, left at the same time. They were then sent to a state-run institution.

An exhibition which opened five years ago, and is still running today at the Ballenberg open-air museum, awoke modern Switzerland with a shock to its dark past of child exploitation. The man behind it, Basil Rogger, says that from the 1920s on there was a constant flow of pamphlets, autobiographies, and newspaper articles about the plight of the contract children. Their history was not a secret. If you wanted to know about it you could.

By the time of the exhibition, a generation had passed since the practice had died out, and there was enough distance to cope with it. Crucially, he says, the state was prepared to address the issue. Contract children who thought their experiences were isolated realised they were not alone, and began to share their stories.

Visitors also began to ask questions within their own family - Rogger says when he met people weeks after the exhibition they would tell him someone in their family was a contract child. "So people became aware of the omnipresence of this system, because almost any Swiss person knows someone placed in a foster family."

In recent years there has been a process of national soul-searching. Last year an official apology was made to contract children, and other victims of the state's compulsory measures - people who had been forcibly sterilised, or unlawfully detained.

Image copyright Paul Senn

The Swiss Parliament, the Bundeshaus is buzzing. The campaigner Guido Fluri has just got the 100,000 signatures for a petition that could put the question of compensation to a national referendum. It's calling for a restitution package of about 500 million Swiss Francs (£327m) for the 10,000 contract children estimated to be alive today, as well as others wronged by the state's coercive measures. The petition was launched in April. Fluri says its success shows how strongly the Swiss people sympathise with the contract children.

Image caption Guido Fluri Many who have experienced such severe suffering feel that wounds are being reopened Guido Fluri, Campaigner

He is in parliament lobbying politicians to win their support for the petition. He explains to parliamentarians the plight of survivors - "people who suffered for decades, who fought, who were never able to leave their trenches, who hid away, who were ashamed of their story… some of whom are living in neglect". It's not just money, he says. "What's important is to point the way towards acknowledging that huge suffering."

The Farmers Union agrees with the principle of compensation, but is adamant that farmers should not have to contribute. You have to understand the times in which these children were placed into foster care, says union president Markus Ritter. Councils and churches had no money. Farming families were asked to take children who had fallen on difficult times or had one parent so the farmers were fulfilling a social function. Does he acknowledge abuse occurred? "We received a lot of feedback from children who were treated really well… But we are also aware that some children were not treated properly."

Guido Fluri says this social re-examination is liberating for some former contract children. Many elderly people come on crutches and in wheelchairs to his office to discuss their stories with him. The other day he found a poem left on his desk. For others, public discussion is too much to bear, and Fluri has received death threats. "Many who have experienced such severe suffering feel that wounds are being reopened," he says. "You can understand. They are completely overwhelmed by the situation."

It's taken a long time for the drive for compensation to reach this point, and there could still be many years of parliamentary discussion more before it becomes a reality. Loretta Seglias says the issue of restitution is a complicated one in Switzerland. "There is this fear of having to pay compensation... Some will say who else will come forward?" The experience of war reparations has left a scar.

David Gogniat, who left his foster family when he was 16, is now 75. He runs a successful trucking business. He arrives with his wife at the Bern archive. Since July, former contract children have had the right to access their childhood files.

David started the search into his past two months ago. He waits nervously outside in the autumn sunshine.

Many are probably afraid to read those files because they don't know what to expect Yvonne Pfaffli

"To me it feels as though there was some sort of an agreement between the farmers and child services to provide children as cheap labour," he says. But he only wants to know one thing: "Who was responsible for the fact we were taken away?"

He accepts that he may end up feeling disappointed, but he also thinks this could help him move on.

Once inside, he waits in a modern glass room. Yvonne Pfaffli, who has found his records, arrives with two files. I leave David in private to absorb it all. A while later, earlier than I expect, he emerges.

"Things came to light that I hadn't heard of or seen before, and I think I need to look at it again some other time," he says. Later, he tells me he learned something about his father, and some intriguing financial information - but he doesn't divulge details. He just seems relieved to have held the files of his childhood in his hands.

Over many more visits to the archive he will now try to piece together the mysteries of his past.

Many people have big gaps in their knowledge, says Pfaffli. They may remember being taken away in a black car, without ever having known why.

"They didn't know that it might be the result of something like their parents' divorce," she says. "These are very big questions, and many are nervous, and many are probably afraid to read those files because they don't know what to expect, but on the other hand they are hugely grateful that these files exist."

The documents have usually been written by social services staff and their perspective may be very different from the child's. There tends to be no mention of abuse.

Image caption Yvonne Pfaffli with files from the archive

Sarah, now 51, left her foster family at 15 for an apprenticeship and never went back. She too has her file, though she was shocked at some significant omissions. Letters from her school doctor and teacher expressing concern about the way she was treated are not there, she says. Neither is a letter from the local authority apologising for placing her with an inappropriate family, which she says she was only ever allowed to read and not keep. With the help of the Verdingkinder network she is trying to trace them.

"What's also missing is the bit explaining why I was placed in that family in the first place, who made the decision, how it even came to that, so my files are anything but complete," she says. "And that's a shame. All we want is our story, and then we can draw a line under it… I am by no means certain whether the authorities aren't just putting up a front when they say they're helping us. For me there is a question mark."

Christian got his files back in July. "It's very very important. It's my life. It's also important for coming to terms with it in a historical and scientific way," he says. He has many questions: why they were taken away, and why so far away from their mother? Did the authorities know about the work they were doing. Did they know about the polio-arthritis he began to suffer from while living with the foster family? He says the report from a psychologist that triggered his removal from the farm is missing. He is still studying the 700 pages.

He shows me letters from his mother documenting her concern about her sons' health and the fact that they were not allowed to go to secondary school.

There is a contract with the farmer showing his parents' contribution to the foster family of 900 Swiss Francs a month, later increased.

But some former contract children find that no files remain. "Either they have been destroyed a long time ago, or more recently," says historian Loretta Seglias. "Some get answers… others don't."

Image copyright Tbc Image caption Two unidentified contract children

Christian's foster parents agree to meet me - and are open to meeting him. One early morning we make the journey to the countryside.

Before we get in the car, Christian tells me he doesn't expect an apology, but by talking about what happened, he thinks, maybe they will reflect on how they behaved. As we drive into the countryside the views are breathtaking. Christian looks out of the window. "I am feeling very complex emotions. The landscape that used to give comfort to me as a child is giving me comfort now, but I'm also a bit speechless. It's difficult... I am feeling nervous as I have no idea what will happen there."

As we enter the village, Christian points out the village shop where he used to steal chocolate as a child. It's had a makeover three decades on. He becomes palpably anxious as we approach the farm. He wants to be left at a nearby river while we conduct the interview.

I approach the picture-postcard farmhouse. After some time, the farmer and his wife emerge. They agree to talk but on the condition of anonymity. They deny all of Christian's allegations - describing them as "lies". They say he never worked before or after school… maybe during the holidays he swept the stables. And they insist they were never violent towards Christian or his brother.

"No. You shouldn't hit children," says the farmer. "On the contrary" says his wife "with hugs, we tried with love." I mention the mock-castration, "Ha, castrate!" the farmer shouts. "What else? Those are some memories he has!"

Image caption Farmhouses have been erected at the museum to show traditional rural life in Switzerland

It infuriates him when I say Christian said he felt as if he were a contract child. "No, he wasn't a contract child, he was no contract child, we had them as if they were our own children," says the farmer.

I don't know where my journey will take me, I just know I want to fight for something Christian

I ask how it feels three decades on to have these allegations made against them. "It's a saddening feeling, very sad," says the farmer. His wife adds: "I was so attached to those two."

But they refuse to see Christian. "We congratulate him on those lies he cooked up!" she says. The farmer adds: "I wouldn't even look at such a person with my backside."

Afterwards, I tell Christian there will be no meeting. "In some ways it makes me very, very sad because I was here, he had the opportunity to speak to me… I had prepared myself to talk to him and I would like to have confronted him with these questions in person and seen whether he would also have told me it was lies."

Christian walks back to the car, limping because of his arthritis. On the way back he is silent. Just before reaching home he tells me he has the same feeling of dread he used to have when going back to the farm. He seems fragile.

"I don't know where my journey will take me, I just know I want to fight for something that needs to be done," he says. "And I want to take responsibility not just for my brother and myself but for others in my generation as well."

Because it all happened so long ago, it is no longer possible for charges to be brought against the farmer, should the authorities have wanted to. Very few prosecutions have ever taken place against the foster parents of contract children, or the social workers who failed them.

Image copyright Paul Senn

Sarah's home is covered with pictures of her children and grandchildren. She has a happy marriage. Her family know nothing of her childhood. She keeps the file containing her records away from the house so there is no risk of it being discovered. She attends contract children support meetings in a different city so she won't be recognised.

"I don't want to stand in my children's way - I don't want them to be snubbed because of me because of my past," she says. "Contract children still haven't found their place in society, we're still considered to be on a lower level, or even in the basement. That's why I'd rather the neighbours didn't know."

David Gogniat used to be Bern president of the Hauliers Association, and some members found out recently that he had been a contract child. "It then turned out some people I had done business with had grown up just like me," he says. "They later founded a club and a few weeks ago they invited me to visit, so I am now a member."

His goal is to get compensation for former contract children. "I was lucky to be healthy so I was able to work and managed to make a life for myself," he says. "But many were not that fortunate."

Christian, now 42, is an artist. His home is decorated with his sculptures and pictures. His career choice is no coincidence. "My brother and I were never encouraged to put our feelings into words, to describe them, and of course to express them without fear," he says. "Somehow I felt in art I learned to talk about my inner thoughts, the images inside me and also about the external impressions and images, so this path was very, very important for me."

Image caption Christian's mother, 2014

His relationship with his mother has been damaged. "These events have completely torn my family apart," he says. His mother agrees. "I would say we have grown apart, we don't really have much in common," she says. "It's very difficult, even now."

Christian says the experiences of his childhood have left huge scars.

"You understand you are different, but you don't want to be different, you'd somehow like to be normal, you'd like to pretend this had somehow never happened."

Archive photos of verdingkinder courtesy of Paul Senn (1901-1953), Bern Switzerland; Bernese Foundation of Photography, Film and Video, Kunstmuseum Bern, deposit Gottfried Keller Foundation. © Gottfried Keller Foundation, Bern.

Watch Kavita Puri's report Switzerland: Stolen Childhoods on Our World at 11:30 GMT on Saturday 1 November and at 2230 GMT on Sunday 2 November on BBC World News channel. In the UK, go to the Our World programme page. Assignment is on BBC World Service radio from Thursday.

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