Figures show almost 14,000 pupils aged 7 to 13 are boarding at private preparatory schools in Britain this year – an increase of more than five per cent in just 12 months.
More schools are also building additional boarding facilities to cater for rising demand among parents.
The number of young girls choosing to board this year alone has soared by almost a fifth to just under 6,000.
But it was claimed that the rise may also be driven by the economic climate, with mothers and fathers forced to work increasingly long hours to make ends meet.
David Hanson, the chief executive of the Independent Association of Prep Schools (IAPS), said many families saw boarding as a cheaper alternative to hiring a full-time nanny.
Some parents are also attracted by the rise in “flexi-boarding” – flexible arrangements that allow children to stay for few nights a week without making a full-time commitment.
According to data, some 13,945 pupils are boarding at schools belonging to the IAPS this year, compared with 13,178 in 2010.
Figures show 218 schools now have boarding facilities, compared with 204 a year earlier.
The average prep school charges an average of just over £18,000-a-year for full-time boarding. By comparison, senior schools charge almost £25,000.
Boarding is believed to be much cheaper than many forms of childcare, with a full-time nanny in parts of the south-east costing as much as £40,000 after tax.
Mr Hanson said: “Busy professionals are realising the benefits of sending their children to these schools, which offer excellent facilities, healthcare, education and social environments, that can give them complete peace of mind, rather than paying for a nanny of uncertain quality.”
He added: “Paying a nanny is terrifyingly expensive. You don’t tend to think about it at the time as you pay it in monthly or weekly chunks, but when you calculate it over the year you’re staggered by how much you’ve spent.”