Two more independent prep schools are closing this summer, with teaching unions predicting that the recession will force more out of business in 2009.
Arley House school in Loughborough, Leicestershire, where Year 1 fees start at just under pound;2,000, has told staff and parents that it is to close.
And Windmill House at Uppingham in Rutland has announced that the pound;2,000- a-year school will shut at the end of the summer term.
Meanwhile, St Mary's Hall junior and senior schools in Brighton will be taken over by nearby Roedean in September. The senior school will close, and pupils will be invited to transfer to Roedean, while the junior school will continue on its existing site.
John Richardson, the Association of Teachers and Lecturers national official for the independent sector, said: "Prep schools are the most vulnerable because they don't have the critical mass to withstand the buffeting. If five pupils out of 100 are pulled out, that might be the tipping point for some."
Mr Richardson said the union expected Easter - when staff-planning for the new year begins - and September to be critical periods for independents this year.
He added: "The last recession took 18 months' filter time and this recession started in April 2008, so we're expecting some fallout from this September."
Jane Peach, chairman of trustees for Windmill House, believes prep schools are particularly vulnerable.
"We haven't spent money on bling and we don't sit in lovely green playing fields," she said. "That affects parents' perceptions.
"And they are saving money, hoping to have enough to educate their children at senior school."
The latest announcements follow other closures, including St Catherine's in Stockport, Cheshire, which shut its doors at the end of last year. In January, Bramcote Lorne Prep School merged with Lincoln Minster School, while Brigg Prep School amalgamated with Hull Collegiate School.
But Diana Watkins, chairman of the Independent Association of Prep Schools, said independents had been reporting that numbers were holding up.
She added: "The numbers have not changed at the moment. Schools are telling us that inquiries are more serious rather than parents coming just to have a look."