Visitors were given a guided tour by deputy headteacher Paul Crisell, of Great Roke, which was built as a country house in 1909 by partner architects, Buckland and Haywood, one of the leading Arts and Crafts architects firms of the Birmingham movement.
The former country house, which has been hailed as one of the finest large houses produced by the Birmingham movement, was eventually taken on by the Josephite Fathers as an all-boys’ boarding preparatory school.
It later evolved into the current co-educational day school, now run by the school’s parent foundation, Bridewell Royal Hospital.
Mr Crisell said: “We have welcomed a large number of visitors on Heritage Open Days over the years.
“They have all benefited from the opportunity to uncover the delights of one of Surrey’s best kept secrets.”