Ruth Miller arrived at the Foundling Hospital in April 1942, just a few weeks shy of her fifth birthday.

She had no idea that her foster parents were not her real parents, and as she stepped onto a coach to begin the journey from Essex to Berkhamstead where the hospital was based, no idea where she was going.

“I remember asking my foster mother whether I would be able to come home for dinner, which in those days was at midday, and she said ‘no’ and I didn’t ask any more questions,” she says.

“As we went in through these huge gates, I had a premonition and asked: ‘I am coming home tonight, aren’t I?’. She said ‘be a good girl’, gave me a kiss and was gone. That was all the preparation I had.”

This sense of abandonment provides the theme for the latest exhibition at the Foundling Museum, which tells the story of former pupils at the Foundling Hospital, a home for the “education and maintenance of exposed and deserted young children”,

It was founded in 1741 by philanthropist Thomas Coram and based in Bloomsbury until it relocated in 1920 to what was thought a healthier location in the countryside.

With the move away from institutions towards caring for children in families it closed in the 1950s but the Bloomsbury-based children’s charity Coram continues to run numerous services for children.

‘Exchange’ by leading ceramic artist Clare Twomey, features 1,000 cups and saucers each inscribed with a good deed, ranging from simple acts like ‘smile more’ to more challenging ones: ‘don’t use any plastic bags this year’.

Visitors are encouraged to undertake a deed in exchange for a piece; taking the cup but leaving the saucer behind. The act symbolises the heartbreaking exchange made when mothers would leave their children at the Hospital; hoping the loss of a child they were unable to care for would allow them to have a better life.

Mrs Miller, 76, was at the Foundling Hospital for ten years. She didn’t see her foster parents for five of those, and then only during the holidays.

“The idea of the foster parents parting with the child at the age of five was to give the birth mother a second chance, because she was a fallen woman and we were all illegitimate,” explains Miller.

With stoicism typical of her generation, she insists that the children at Foundling were lucky compared to others during World War Two.

They received a decent education in an environment with excellent facilities. Indeed, with 40 acres of land and a swimming pool, the Hospital earned the name: “the bastards’ Eton”.

But daily life was regimented; with a strong focus on order and discipline, and Miller felt that the nurses often belittled the children.

Meals were conducted in silence and all the pupils were given the same hair cut.

Bizarrely during the war, none of the children were allowed within 12ft of the school gate; a fact which caused alarm in nearby Berkhamstead as none of the locals had ever seen the children at the school.

Despite a liberalisation of the rules governing the Hospital following the 1946 Curtis Report; Miller says she was institutionalised during her time there.

“From the time I went into the Foundling Hospital in 1942, the only time I was ever hugged or kissed was when we went back to our foster parents for holidays,” she reveals.

Having left at the age of 15, she struggled to adapt to life in the real world; eventually opting for a career in nursing at University College Hospital.

“It was shameful to be illegitimate,” she explains. “There was a difficulty in talking to someone who you might become friends with if the conversation turned to where do you come from, and where do you go to school it was very difficult to enlarge on it.”

It was at nursing school that she met “the man of my dreams”; only for the relationship to breakdown once the man’s family learnt about her upbringing.

“What are you going to put in the Telegraph about a wedding announcement?” asked his mother when she heard of their engagement.

“You couldn’t put daughter of wing-commander Smith, or daughter of Lord Axford,” says Miller. “I wasn’t the daughter of anyone.”

In later life as the stigma associated with being ‘illegitimate’ decreased, Miller was able to live a more normal life. She got married and had three children, but she and her husband divorced after 16 years. She now lives in Bury St Edmunds.

It was the establishment of the Foundling Museum in 2004 that has really proved to be a source of strength.

“It tells our story. It enfolds us as human beings,” she says. “I love this place. I feel it’s done so much, alongside change in our society, to give us an identity.”

Miller has never met her birth mother bit from what little she knows of her, she grew up in Wales and was staying in Hampstead when she became pregnant at the age 29 and gave birth. The letters Miller’s mother sent to the Foundling Hospital asking how her little girl was getting on were not shown to her until she was well past middle-age.

Every time she comes to the Museum in Brunswick Square she makes the same journey her mother made when she placed Miller into the care of the Hospital in 1937.

“It’s a very powerful exhibition,” she said, gazing at a cup which encourages her to “put the needs of others before my own”.

“It’s exactly right to take something and leave something. The analogy with mothers taking the opportunity to reconstruct their lives and leaving behind the saucer, equated with the baby was extremely powerful to me. And I like the idea of inviting anyone from all around the world, in to what was a very closed society for so long.”

With eight grandchildren, the cup is appropriate because, as she puts it, “I’m always doing that.”

As we leave, she points to a postcard in the museum shop. “That’s me,” incdicating a little girl in school uniform sat at a long dining table in Foundling Hospital.

“You know, it’s taken me 50 years, but I feel quite proud of being who am I now, in a curious sort of way.”

‘Exchange’ runs at the Foundling Museum, 40 Brunswick Square, London, England WC1N 1AZ, until September 15th.