The British nanny is defying a trend in many sectors toward lower pay and longer hours, CNBC reported.

Saudi princes, Russian oligarchs, busy executives and celebrities want a Mary Poppins-like figure to look after their children.

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 markets since the financial crash in 2007. Read more.