London-based nanny agencies seek to attract this elite clientele by capitalizing on Britain's royal heritage. With names such as Imperial Nannies and Royal Nannies, agencies have associated themselves with London's most expensive districts and the U.K's reputation for a high-class education.
Louise Taylor, manager at Kensington Nannies, told CNBC that business had boomed in both the U.K. and overseas market since the financial crash in 2007. "When we thought we'd have this big drop off [in business] we boomed," she told CNBC on Friday. "We have more jobs on the books than we've ever had. Those that had work had to work even longer hours so a nanny became more essential. This is the London market now."
"The overseas market tends to be the super-rich as it becomes more fashionable [to have a nanny]," she added. We have seen a massive increase in demand from families in Monaco,and then there are the clients in Russia and Arab countries [fueling demand]."
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British nannies have a head start over other nationalities as they have English as a first language, the educational background and the "complete prestige" factor demanded by the"super-rich" overseas market, she said.
"This industry is recession-proof. There's always going to be people that have money in England,and abroad," Taylor added.
Another renowned employment agency, Norland Nannies, says it also receives a lot of interest from families all over the world, in particular Europe and the Middle East.
Norland has its own training college and is famous for its uniformed students. Offering full-time degree courses in childcare, its graduates - known as "Norlanders" - go on to serve in households around the world. They can expect to earn a net salary of up to 41,000 pounds a year ($63,400) if they take up a residential placement in a household overseas.
"Positions vary from those [offered by] ordinary families and expats to locals, high profile and Royalty," Liz Hunt, the principal of Norland College, told CNBC.
"There are a number of reasons why our overseas clients want to employ a 'Norland-trained nanny'. These are because of their qualifications and training, their traditional values and the fact that they are bound by a code of professional conduct," she said.
The image of the benevolent but disciplinarian British nanny or governess has been entrenched in popular culture since the Disney film Mary Poppins was released in 1964. It has enjoyed a renaissance too since the television program "Supernanny," in which viewers watched British child expert Jo Frost enter households to help struggling parents with their wayward charges, became a hit series in the U.S.
The Nanny's Experience
Not all nannies have professional or academic qualifications, first aid training or knowledge of childcare, however. One British nanny, who has worked in Riyadh in Saudi Arabia for almost a year,told CNBC of "horror stories" she had heard of the standard of care provided by– and for - other nannies there.
"Maids and nannies from the Philippines in some houses get nothing more than water and rice maybe once a day…Pay gets held back, [they get] no holidays home and they all have a few children back in their country," she said, preferring to remain anonymous.
"The family I work for are pretty decent people and I can't really complain about anything.They decided to go for British nannies because they understand their children would get better care and education because we have had a decent education,"she told CNBC.
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"All the staff our family employ are treated well and fairly, we get paid travel home, food,accommodation, medical expenses, pretty much anything we need," shesaid.
"There's always something new about to happen,you always need a suitcase half full ready to head somewhere with a few hours'notice. We once flew to Monaco only to turn around mid-landing to head back to Paris. Someone had changed their mind about going," she said.
Agencies such as "Royal Nannies" in London have 3,000 nannies, maternity nurses and governesses registered and require over five years' experience. And good nannies don't come cheap. A governess working 50-70 hours per week can expect to be paid between 700 and over 15,000 pounds per week and overseas nanny working 40-70 hours a week could earn between 600 to 1,200 pounds per week, according to a salary guide on the agency's website.
Agencies can command fees for their services of up to 20 percent of the nanny's net annual salary - making it a lucrative trade if a placement if successful.