Two of the country’s leading private schools have defended their decision to turn down a £1m scholarship donation for white boys from impoverished families.

Dulwich College in south London and Winchester College in Hampshire turned down the gift from the philanthropist Sir Bryan Thwaites over fears that it would break equality laws.

Thwaites, 96, who attended both schools and intended to leave the money in his will, wanted the scholarship to help white boys from disadvantaged backgrounds because they perform worse at school than their counterparts from other ethnic groups, according to the Times.

Dr Joe Spence, master of Dulwich College, said he was grateful to the benefactors who support the college’s bursary fund, but was resistant to accepting donations made with any ethnic or religious criteria. He said: “Bursaries are an engine of social mobility and they should be available to all who pass our entrance examinations, irrespective of their background.”

A spokeswoman for Winchester College said: “The trustees are clear, having consulted widely, that acceptance of a bequest of this nature would neither be in the interests of the school as a charity, nor the specific interests of those it aims to support through its work.

“Notwithstanding legal exceptions to the relevant legislation, the school does not see how discrimination on grounds of a boy’s colour could ever be compatible with its values.”

The Times reported that Thwaites intended to give £400,000 to Dulwich College and £800,000 to Winchester College. Day pupil fees are £21,000 a year at Dulwich College and £40,000 a year at Winchester.

Bryan reportedly benefited from scholarships that allowed him to attend Dulwich College until the outbreak of the second world war, when he was sent to Winchester College.

He told the newspaper: “If Cambridge University can accept a much larger donation in support of black students, why cannot I do the same for underprivileged white British?”

Last year, the grime artist Stormzy revealed that he would be funding two scholarships for black British students to go to Cambridge University. In August, the rapper said he would cover the costs of two more black undergraduates. Following the musician’s backing of scholarships, a record number of black students were admitted as first-year undergraduates.

Thwaites added: “Winchester said it would harm its reputation by accepting my bequest, but in my opinion it would gain enormously by being seen to address what is the severe national problem of the underperforming white cohort in schools.”