Families who employ a full-time daytime nanny in London are paying an average of nearly £27,000 a year for their services, a study shows.
Nannies who live with a family earn an average of almost £20,000 in London, according to the study for Nursery World and Nannytax.
More parents were employing nannies on a part-time basis, the survey added.
Andrew Myers, of Nannytax, said: "The modern day Mary Poppins is no longer simply the preserve of the rich."
Full-time nannies in the Home Counties earn £22,514, while the figure is £19,355 in other cities and towns and £18,939 in rural areas, the survey found.
Demand is expected to grow further when a scheme offering tax breaks and employer vouchers for parents employing approved nannies is introduced in April.
Liz Roberts of Nursery World said: "Having a nanny is a flexible form of childcare for many families and the new tax breaks should make this an increasingly affordable option for those on lower incomes."