Farnes had been commissioned as a Pilot Officer on 1 September 1941, having served first in the ranks and trained as a pilot in Canada. He was posted to No.12 Operational Training Unit at RAF Chipping Warden, near Banbury, where new bomber crews flew Wellingtons by night before being released to operational squadrons.
On the night of 20 October 1941 he took off on a routine night-flying exercise. The aircraft crashed almost immediately after leaving the runway, killing Farnes and several of the crew. The Air Ministry recorded the cause as 'lost control on take-off, night'. He was buried at Brookwood Military Cemetery in Surrey, where his headstone still carries the simple inscription 'Cricketer'.
The news travelled quickly through wartime cricket. Essex captain Tom Pearce paid tribute; Wisden's 1942 almanack noted that England had lost a man who would surely have spearheaded the post-war attack. Farnes had taken 720 first-class wickets at 21.45, including a fearsome 11/76 for The Gentlemen v The Players at Lord's in 1938, and had been part of Hammond's tour of South Africa in 1938-39.
Unusually for a fast bowler of his era, Farnes was also a published author and a teacher at Worksop College. His wartime memoir Tours and Tests was published posthumously in 1940.