Alley Lofthouse was only hours old when she was abandoned on a doorstep in Grangemouth.

It was a bitterly cold February morning when paper boy Hamish Brown stumbled across her.

At first he thought the misshapen bundle inside a pillowcase was a discarded teddy bear and was about to kick it aside when it made a sudden jerking movement.

Peeling back the thin material he discovered a baby girl, freezing cold and naked. She was covered in blood and mucus, her umbilical cord still attached.

Brown raised the alarm, rousing the occupants of a nearby flat. The baby, suffering from hypothermia, was rushed to nearby Falkirk Royal Infirmary where nurses named her Heather.

Later adopted by a family in Cumbernauld who renamed her Alison, more than four decades on she is no closer to finding out how she ended up on that doorstep. In the weeks that followed the police appealed for her mother to come forward but to no avail.

Lofthouse is under no illusions her story could have turned out very differently. "I wouldn't be here today if someone hadn't found me when they did," she says. "It's unlikely I would have survived much longer on that doorstep. I have been told I was freezing cold to the touch."

Now a married mother-of-three living near Hull in Yorkshire, Lofthouse is spearheading a campaign to champion the rights of abandoned children – or foundlings as they are known – calling for the introduction of "baby hatches" at hospitals and other public buildings across the country.

Dubbed "cradles of hope", the scheme would allow mothers to leave their babies anonymously in a safe and secure location, a system which is already in widespread use in countries such as Germany, the Czech Republic, France, Austria, Italy and Poland.

It is a practice which dates back to medieval times, when babies could be left at something known as a foundling wheel. At present, baby hatches are illegal in the United Kingdom.

Lofthouse, 45, has launched an e-petition calling for an amendment to section 27 of the 1861 Child Abandonment Act which makes it an offence to desert a child aged under two. She believes the law stigmatises mothers who can't cope with their babies by branding them criminals and wants to instigate a change which will allow parents to surrender their offspring in a designated safe place free of prosecution.

The US already has a similar "Safe Haven" law under which babies up to 72 hours old can be deposited in locations such as hospitals, police and fire stations. "In many hospitals they have a separate door off the accident and emergency ward through which you can anonymously access a room," explains Lofthouse. "There are no CCTV cameras, but it triggers an alarm. Once they leave the baby and the door shuts behind them, only then are the doctors and nurses allowed in.

"My vision is to have baby hatches in major cities and towns across the UK as well as places in rural areas for people to surrender babies anonymously and safely."

It is estimated that between 25 and 50 newborn babies are abandoned in Britain every year. In many cases their parents are never traced. Approximately one-third are reunited with their birth mothers, while another third are put up for adoption and the others, sadly, do not survive.

In recent years, babies have been found dumped in carrier bags, behind bushes, in public toilets and rubbish bins. Last October the body of a baby girl was found dead in a river in Kirkham, Lancashire. In March 2010 a baby boy left wrapped in a towel outside a shop in Wales died after villagers mistook him for a gym kit.

"The reasons why women abandon their children can be complicated – it's not as cut and dried as people might think," says Lofthouse. "The mother may have been a victim of rape or incest. She could be someone who can't have a child out of wedlock for cultural or religious reasons.

"A baby that died [in 2010] after being abandoned in Birmingham was half white, half Asian. Honour killings are illegal but they do happen – it would be naive to think otherwise. It [having a mixed-race baby] remains a huge stigma.

"Poverty is playing a bigger role too. In Greece, statistics show the number of abandoned children has increased tenfold since the economic crisis began. Families are asking the state to take their children because they can't afford to look after them. If this is happening in a country like Greece, where family is such a big institution, it makes you think, could it happen here?"

Yet it is an idea not without controversy. The United Nations has questioned the legality of the hatches, or baby banks as they are also known, claiming they violate children's rights. Those who oppose the system believe its introduction would make it easier for women to abandon their offspring.

Among those who share these fears is Lofthouse's half-brother Iain Hogg, who was also abandoned by their mother as a baby. Hogg, 43, a businessman from Callander, Stirlingshire, believes baby hatches are a licence to abandon newborn infants.

"It's an easy option," he says. "If you put something like this on our doorsteps –where people can give up their babies, no questions asked – it will normalise the whole thing. When they introduced a similar scheme in America there was an increase in the number of babies being abandoned. It is my fear we would see the same thing here.

"For me it conjures up an image of a row of skips: bottle bank, clothes bank, paper bank, cardboard bank, baby bank. Could you imagine seeing that? Picture a man turning round to his wife and saying: 'Right, I'm off down the skips. I've got the bottles, newspapers, old clothes – is there anything else you need me to take?' and she replies: 'Aye, I can't afford any nappies this week. Can you take the baby with you?'

"That's why I say to Alison: 'You are totally wrong.' She is my sister and I don't want to fall out over it, but at the same time, if I saw she was getting somewhere with this, I would need to step in and try to stop it. As a father of four children I don't feel it's right for someone to pick up their child, drop him or her at a baby bank and say: 'Cheerio, I'm away.' It reflects what a disposable society we have become."

Lofthouse acknowledges her brother's concerns but insists the overwhelming public response has been positive. "If we have baby hatches, yes, there may be an increase in the number of babies being left, but what happened in America was that there was also a rise in the number of mothers coming back to get their children afterwards," she says. "You can't do that with a dead baby.

"With baby hatches the mother has the option to come back in the weeks that follow and say: 'I made a mistake.' Then a whole network of support should kick into place to help her."

Another key issue which needs addressed, she says, is that there is no clear policy in the UK regarding what should happen after an abandoned child is found. "In some cases a child could stay in foster care for a year, 18 months or two years before social services decide the case is closed," says Lofthouse. "That is unfair to the child. I believe there has to be a restriction on that time frame. In America it's eight weeks, in other countries 10 weeks.

"Another reason for women abandoning babies is that pregnancy can trigger mental health issues. Physically as a mother, within eight to 10 weeks, your body will usually revert back to normal. So, if it is a hormonal thing, she could suddenly think: 'What have I done?' and want her baby back.

"You need to allow time for that to happen, but you can't leave the baby for too long in that limbo state either because you miss out on that bond the child will have with another family. It's important for the child to feel secure.

"Regardless of how secure your upbringing – and I had a wonderful childhood – sometimes I still feel insecure and unsure of myself. I believe that does come from being abandoned as a baby. There is always that lingering question: 'If my mother could leave me, who else could leave me?' It is a nagging doubt; your mind plays tricks on you. I have a very happy family life, but I still have moments where that issue rears its head."

Lofthouse was six months old when she was officially adopted. While her birth mother didn't respond to police appeals, another woman, Nancy Mitchell, did see the newspaper stories.

Nancy, then 27, was married to 31-year-old civil engineer Harry Mitchell and they had two sons. Unable to have any more children, Nancy longed for a daughter.

She and Harry were one of several couples who applied to adopt Heather, and she came to live with them in their semi-detached house in Cumbernauld. They renamed her Alison Margaret Mitchell.

While she always knew she was adopted, it wasn't until Lofthouse was 14 that she discovered the truth about her parentage. Nancy broke the news over dinner, handing her a file of newspaper cuttings. "I was shocked but I wasn't upset," she recalls.

Instead she felt sympathy for the woman who abandoned her. "My empathy comes from my mum [Nancy]," says Lofthouse. "During the adoption interviews they asked everyone how they felt about my birth mother and most people said: 'She should be strung up.' My mum [Nancy] said she felt sorry for her because she would never know what her daughter looks like or the person she grows up to be.

"I don't know this person [her natural mother]. She gave birth to me, but I can't make a judgment about her when I don't know the circumstances. Having had my own children I know that it must have been something desperate. Even after she abandoned me her body would have gone into shock and mourning because it was prepared for a baby that wasn't there. It must have been devastating."

In the living room of her home, Lofthouse flicks through an album of newspaper cuttings. She admits pondering the gamut of possibilities as to what led her mother to leave her. "I've wondered whether she was really young, was it down to money, was she on her own? Then there is also the fact that Grangemouth was a merchant sea port back then and it did have quite a lot of prostitutes, so that is another scenario."

Married to David, a 44-year-old finance officer, with whom she has daughters Jessica, 17, Emma, eight, and Hannah, five, Lofthouse says growing up she always worried there could be something hereditarily wrong with her which would see her abandon a child too.

"I had a great fear it was something inbuilt and genetic. I wondered if I had a baby, would I reject it the same way? When I had Jessica, though, I knew as soon as I saw her I would never leave her.

"While I was relieved, at the same time I felt a sadness as I looked at Jessica lying on my chest. I thought of me, on the ground, in a pillowcase and wondered: 'How could you?'"

Yet the curiosity about her natural mother has never left her. "I would still like to meet my mother and find out what happened," says Lofthouse. "Is that for a sense of closure? More nosiness, I think. At the end of the day, though, I have three kids and need to be careful about who I bring into their lives."

It is unusual for foundlings to have siblings who have been abandoned by the same mother, but eight years ago Lofthouse discovered she had a half-brother who was left in a public toilet in Grangemouth 18 months after she was found.

The pair were reunited after Lofthouse launched a public appeal and a DNA test later confirmed they shared a mother. Like his half-sister, Hogg was found wrapped in a pillowcase. Doctors believed his mother had looked after for him for at least a day; he was washed, fed and dressed.

This time, however, there was a description of their mother after someone reported seeing a woman going into the toilet carrying a bundle. She was described as aged 20-25, medium build with dark hair, a sallow complexion and wearing a raincoat and a dark woolly hat.

Hogg was adopted by Ian and Yvonne Hogg, who lived in Bridge of Allan, Stirlingshire. The couple already had two young children and went on to have another son and adopt a daughter.

"I had a wonderful childhood," says Hogg. "From an early age I always knew I was a foundling, but it never worried or upset me. I was always surrounded by so much love from my parents and siblings."

He is married to Helen, 42, and the couple have four children. Unlike Lofthouse, Hogg doesn't want to track down their birth mother. "I have no interest in meeting her," he says. "My mum and dad are the ones who brought me up, they fed and educated me, they loved and looked after me. I have my own kids now and the way I look at it is, whoever this woman who gave birth to me was, she is not part of my life – and nor do I ever want her to be.

"Who would I be inviting into my life? Do I want to go through a scenario of meeting someone who has abandoned two babies? The answer is no. There is no curiosity. I look forward more than I look back."

Despite her half-brother's misgivings, Lofthouse is pushing ahead with the campaign. She requires at least 100,000 signatures on her petition for the issue to be debated in Westminster and continues to lobby support.

"All of the adoption agencies I have spoken to have come back with the same standard answer: 'Yes, we would like to see some changes in the law, but, no, we don't agree with baby hatches because families need information,'" she says.

"I think that's really naive. If you asked me: 'Would you rather be alive or have the name of your mother?' I would choose being alive. No matter what, people are always going to abandon babies when they feel they have no other option, so why not let them do it safely?" n

For more information visit www.afoundling.co.uk. What do you think about baby hatches? Email susan.swarbrick@heraldandtimes.co.uk.