The London school has more than 140 asylum-seeker pupils from South America, Africa, the Middle East and the Balkans.
The pupils act as translators between staff, children and parents, a vital role because more than 55 languages are spoken in the school.
Robert Singh, the headteacher, said supporting the asylum-seekers added to the school's financial difficulties. But he said they helped to foster a caring atmosphere that benefited other pupils.
Language difficulties mean that some asylum-seekers reveal their full potential only in music and art lessons.
Several African refugees have joined the school's award-winning choir, although they do not understand the lyrics. Others have surprised staff with the speed with which they learned English.
"We've had three children from the Congo who saw their family being killed before their eyes," Mr Singh said. "The eldest brother left last term with level 5 results in English and mathematics."