Three top private schools in Scotland have been told to provide more help for pupils from low income families or risk losing their charitable status.
The Scottish Charity Regulator, which is reviewing 40 private schools, said results so far had shown 10 passes.
St George's School for Girls and Fettes College in Edinburgh, and St Columba's School in Kilmacolm, Inverclyde, failed and were given 18 months to improve.
Charitable status exempts schools from millions of pounds in rates and tax.
Establishments which have the status do not pay corporation tax and receive an 80% discount on their rates.
To qualify for the status, any body must pass the charity test defined in the Charities and Trustee Investment (Scotland) Act 2005.
The test sets out the standard that all charities must meet in providing public benefit.
Where there are conditions on the public gaining access to the benefit, such as fees or charges, charities must demonstrate that they have taken steps to ensure these are not "unduly restrictive".
The Scottish Charity Regulator said that in its evaluation, St George's School for Girls, Fettes College and St Columba's School had failed to pass the test.
It took the view that "insufficient measures had been taken to provide assistance in respect of high school fees, or to otherwise widen the access to the benefit they provided".
Each school has now been issued with directions instructing them to widen access within 18-months.
Scottish Charity Regulator chief executive David Robb said the review being undertaken was "aimed at maintaining public confidence in charitable status".
"Charities must provide public benefit, and that is what the legislation requires us to ensure," he said.
"While 10 of the schools have shown that they do provide a sufficient level of public benefit, we have found that three do not and we have therefore issued them with directions to comply with the legislation passed by the Scottish Parliament.
"We look forward to a positive response from these charities as they set out how they intend to address our concerns."