Staff at Dulwich College - one of London's oldest independent schools - defended the decision to invite the openly-racist BNP to give a lunchtime lecture by saying that the school was in the "business of educating boys in political literacy".
"We want to win hearts and minds, and I'm quite sure on the day we won some new sympathisers," said BNP spokesman Michael Newland, whose party wants all immigrants repatriated.
An Asian sixth-former invited the BNP into school. Previous speakers have included representatives from the Socialist Workers' party and the Anti-Nazi League.
Dulwich master Graham Able denied reports that 200 boys, many from ethnic backgrounds, had "heckled and booed" the speaker. He said that his pupils' opposition to racism had been "undoubtedly strengthened".
"I am glad to say the boys attacked his policies vigorously and treated his views with the intellectual contempt they deserve," he added.
Deputy master Chris Field said pupils ought to be "conversant with all the politics of the day". He added: "They need to be taught different views. I'm a musician and it would be like me saying boys should ignore punk and heavy metal and only listen to classics."
The Independent Schools Information Service said Dulwich's actions were "perfectly defensible" and that it was "a matter of judgment for individual schools".
However, Sir Herman Ouseley, chairman of the Commission for Racial Equality, condemned the speech which he said had nothing to do with education.
Lloyd Marshall, head of neighbouring state school Dulwich High, said: "I'm quite sure some parents would deplore this."