Single mum Samantha Pooley was delighted to be offered the job of researcher with a head-hunting firm in central London. The problem was the hours. Samantha, 23, was told there would be some early morning meetings and evening engagements. As she has no family nearby to look after her daughter, Daisy, four, childcare posed a major problem.

But Samantha found an answer in the Pippa Pop-Ins nursery, close to her home in Fulham, west London. The nursery is one of the few in the UK to offer 24-hour care.

From the age of two, Daisy has attended the nursery five days a week, from 8.15am to 6.45pm. But if Samantha has to leave home early or return late, Daisy sleeps there too.

“It’s a godsend,” says Samantha. “At Pounds 40 a night it makes a big dent in my salary so I use it only when I have to. But it’s worth it. Daisy loves it and it’s better than using an agency babysitter or palming her off on friends. She gets continuity and I can relax knowing she’s happy and safe.”

Another establishment offering a night-time service is the Norland Children’s Hotel, in Hungerford, Berkshire. And in Wolverhampton, the Playdays nursery plans to offer overnight care within the next few months.

But in most parts of the UK, such services are unavailable - even though a 1994 survey by the Daycare Trust, the charity that campaigns for an integrated education and care system, showed many parents worked atypical hours, particularly women in nursing and retail, and there was a growing demand for childcare services not based around the nine to five day.

According to Lucy Lloyd, the trust’s information and policy manager, many mothers who work shifts are forced to cobble together multiple, informal, and often unsatisfactory arrangements with friends or childminders. Children can end up going from playgroup to nursery to childminder to a neighbour. “There’s a need for flexible childcare and overnight nurseries have a part to play, ” Ms Lloyd says.

Playdays deputy manager Lisa Broome says the nursery decided to start a night-time service for children from three months to five years because it had many requests from parents who worked shifts.

“Since we announced our plan we’ve had four or five other nurseries ringing for advice. In time, many will follow suit,” she says.

Because of legal problems, the nursery will initially take a maximum of three youngsters. Eventually, though, it hopes to accommodate up to 12 children for two to five nights a week.

The local authority has told owner Melanie Rowley that a lack of legislation on 24-hour nurseries that take more than three children overnight means Playdays could not be registered under the Children Act and could face prosecution.

The only way round the problem is to class the nursery as a children’s home, like Pippa Pop-Ins, but Mrs Rowley refuses.

Manager Muriel Williams explains: “We don’t want to be called a children’s home. We won’t be taking children 24 hours a day - it is not good practice. We’ll have children during the day or night, but not both. We’re talking to our MP to see if he can sort the situation out.”

Whatever happens, the nursery is determined to start a limited service in the next couple of months. The starting charge will be Pounds 18 a night, from 7pm to around 7am. Children will do quiet activities in the evening, then have a light supper before a bath and stories. “We’ll be making bedtime as much like home as possible,” Mrs Williams says. “Parents can relax knowing their children are in a safe, friendly environment with registered staff.”

There has been little research into the effect on children of overnight care. But Edward Melhuish, professor of human development at the University of Wales, Cardiff, says Israeli studies show it is usually accompanied by extended separation from the parents, often for several days, which can be harmful.

“To make any sort of childcare work, people must have a great deal of commitment to the children. This is particularly difficult over extended hours,” he says. “The studies have shown increased incidence of poor social development in children separated from their parents for long periods, especially younger children.”

Rosemary Murphy, chair of the National Private Day Nurseries Association, also has reservations. She says because more women are returning to work after having children, night nurseries will probably spring up in areas where many mothers have to work shifts. But she does not want to see them everywhere.

“I worry about the children,” she says. “I wouldn’t like them to be left for weeks on end. And from a provider’s point of view, the financial implications are off-putting.

“Employers shouldn’t expect mothers of young children to work difficult hours. Any government worth its salt should make it easier for employers to fix patterns of work for young parents.”

No one wants parents dumping their children on night nurseries. But without one near her, Samantha Pooley is convinced she would have ended up on benefits.

“It’s important that I continue my career and secure a sound financial future for Daisy and myself,” she says. “Without the night nursery, I couldn’t do it.”