The number of nannies employed by families is burgeoning, but they remain the only people working with young children who do not have to be registered.
Now calls are growing for this loophole to be closed.
New research by the magazine Nursery World, published this month, shows that of nearly 70 nanny agencies surveyed, four out of five believed registration would help protect children, while more than 90 per cent thought it would raise the professional status of nannies.
"It's an issue that people are raising more and more,'' says Ruth Beattie, editor of Nursery World. "The number of mothers of under fives going out to work is rising - by the year 2000 one in three is going to be the family's main breadwinner - so it's a growing area. Nannies themselves want to be seen as professionals. They don't want to be seen as people doing a bit of baby-sitting on the side. At our last nanny conference delegates voted overwhelmingly for it."
Some employment agency representatives remain sceptical, saying a registration scheme would be cumbersome and push unregistered nannies underground, but she says: "It's been worked out for child minders. Anyway, the safety of children is paramount."
Under the 1989 Children Act all child minders have to be registered with their local authority, and are subject to annual inspections, and to limits on the number of babies and children they can look after. But nannies - defined as people employed by parents to look after a child mainly in the child's own home - can operate freely.
The employment of nannies is a notoriously unregulated business, open to abuse from all sides. Nannies vary from the trained and experienced professional, earning up to Pounds 300 a week, to the teenager from round the corner, paid in pocket money. They can be employed through a nanny agency, which may run background checks, or found through an advertisement in a newsagent's window.
Nannies have to take their employees on trust. Their hours and duties vary, and they have little job security. Many arrangements work smoothly, but in a relationship based on the two most precious and personal areas of a family's life - their children and home - things can go badly wrong. "Nanny from hell" stories abound among families employing nannies, while "family from hell" ones circulate just as widely among nannies.
A register, campaigners say, would go some way towards protecting children, parents and nannies. Deborah Lawson, council member of the Professional Association of Teachers and chair of the association's nursery nurses committee, says registration would promote the professional status of nannies, and reassure parents that they were employing a properly registered person. It would enable local authorities to get a comprehensive picture of childcare in their areas, and offer a way for parents to register any concerns or complaints about a nanny.
"The main aim of it would be to say, 'this person is competent to work with children'," she says.
Although no details have been worked out, any scheme is likely to be modelled on that set up for child minders, and require personal and police checks to be run on people registering.
But there are practical problems. "Nannies are notoriously mobile,'' says Deborah Lawson, "so whether a local authority scheme would work, or whether you'd have to have a national register is something that would have to be looked into."
Another unanswered question is who would pay for administering it. No-one is rushing to pick up the bill. A further question concerns who, exactly, would be allowed on it.
The Professional Association of Nursery Nurses would like to see a national register of trained and qualified people. "We are aware of the danger that such a register might drive unqualified nannies underground,'' it says, "but it is our view that, once such a register was established and once parents knew of its existence, unregistered nannies would rapidly become unemployable.'' Under such a scheme, nannies would be inspected annually, and also have to update their registration every year.
Such a scheme, it says, could also encourage training by requiring applicants to have attended courses in areas such as first aid, child development and safety in the home, and offer a means of keeping nannies informed about support networks and training courses.
But many nannies and parents remain sceptical.
"I wouldn't mind registering as long as it didn't cost me anything,'' says Lesley Winterson, who has worked as a nanny in London and Somerset as well as overseas. "But it won't do anything to stop bad nannies from working. Nothing will. Some families are unbelievable. They don't even check references. You could be anybody walking in and looking after their children.'' Trained nannies, she also points out, are much more expensive than untrained ones, and many families can't afford them.
While Susan Young, who shares the nanny of her 16-month-old daughter with another family, says: "In theory it's a jolly good idea, but in practice it can only be as good as the people giving the information, can't it? I can't really see how it would do anything I hadn't done in following up references."
It could, she says, be useful if it became a way of finding a nanny. It could also be useful for parents whose companies offer a childcare allowance.
At present, her company, News International, gives Pounds 30 a week to employees using registered childcare workers such as a child minder, or nursery nurses, but parents employing nannies do not get it.
"I can understand that they don't want people just passing the money onto mum, if she's the one looking after the baby,'' she says. "But Nicky, our nanny, is a legitimate employee. She's qualified. We pay her tax and everything. We should be entitled to the allowance."
If nannies were registered, she would be.