British engineer who, as the leader of the Bawdsey Research Station during World War II, developed Radar, which helped the Royal Air Force win the Battle of Britain.
At age 15, he was hired by the London Meteorological Office to track storm patterns in an attempt to make flying safer.
In 1935, he showed the capabilities of his invention by tracking a British bomber eight miles away.
His second wife, Dame Kathryn Jane Trefusis-Forbes, was the director of the Women's Auxiliary Air Force.
He was a direct descendant of the steam engine inventor James Watt.