John Herivel: Belfast born mathematician who played a vital role as World War Two codebreaker remembered with blue plaque

John Herivel was a former pupil of Methodist College from 1924-1936. He was born on August 29, 1918 in Malone Avenue to John Jamieson Herivel (from the Channel Islands) and his wife, Josephine Allison Moat whose ancestry can be traced back to a rich Ulster-Scots heritage. During the Victorian era the Moats were well-known stationers and printers in Rosemary Street, Belfast.

After leaving Methodist College in 1936, John Herivel won a scholarship to study mathematics at Sidney Sussex College, Cambridge. He was a gifted mathematician and whilst at Cambridge, John was tutored by Gordon Welshman. At the age of 21, Welshman recruited John to come and work at Bletchley Park. He commenced there in January 1940 and worked alongside Alan Turing in Hut 6 and others of like mind.

John Herivel’s lateral thinking shed light on the way Germans operated the Enigma machine that encrypted military messages. His way of breaking the Enigma ciphers became known as the ‘Herivel Tip’ or Herivelismus. His simple but truly amazing breakthrough in codebreaking won him special praise by Winston Churchill upon a secret visit to Bletchley.

After the end of the war, John returned to Belfast where he obtained a teaching post at Campbell College. Later, he moved to become a reader In History and the Science of Philosophy at Queens University. 1975 saw John, his wife and family move to live in Oxford where he became a Fellow of All Souls College. He died suddenly aged 92 after a major heart attack and is buried in Oxford.

Chris Spurr, Chairman of the Ulster History Circle, said: “John Herivel was an insightful mathematician whose intuition discovered a way to break Enigma ciphers by hand. His ability in maths was encouraged at Methodist College, and the Ulster History Circle is delighted to commemorate this mathematician and codebreaker with a blue plaque. The Circle is particularly grateful to the Ulster-Scots Agency for their financial support towards the plaque, and to Methodist College for their valued assistance.”