The Centre for Charity Effectiveness at Cass Business School modified its response to a report from the True and Fair Foundation after receiving a complaint from the foundation’s lawyers, the school has said.
The True and Fair Foundation, founded by the philanthropists Gina and Alan Miller, published a report in December which said that one in five charities spend less than half of their income on charitable activities.
A response from the Centre for Charity Effectiveness to the report said it was "worthless and designed to appeal to those...who believe that all charities should be small and run by unpaid volunteers".
A statement appended to the Cass response on its website says: "Following the publication of its response to the True and Fair Foundation’s report, the Cass Centre for Charity Effectiveness received, in January 2016, a legal complaint from solicitors acting for the foundation and its trustees Gina and Alan Miller. The response was removed in order to consider their complaint and to take legal advice."
The statement says the response had been re-published "with one or two minor amendments".
"The Cass Centre for Charity Effectiveness believes it is essential for academics and others to be able to express their views on matters of public interest without fear of being sued for libel," the statement says.
"It welcomes responses to its output and always considers them but believes that such responses should seek to further any debate rather than shut it down. It hopes that the True and Fair Foundation’s trustees will themselves engage in public debate with Cass, rather than spending money instructing lawyers to do so."
A spokeswoman for centre was unable to confirm precisely what changes had been made but said they were minor.
Gina Miller said that she was surprised that the centre had taken the decision to republish the response because she considered that negotiations were continuing.
She said the centre's response contained "between 20 and 22 inaccurate or libellous statements", such as mistakes about the True and Fair Foundation's charitable expenditure and an accusation that the foundation's work was being carried out for "unscrupulous ends".
She said she would be publishing a full response later today.