Follow John Jeffreys through 2 dated historical records for Great Britain.
A chronological timeline drawn from matching World History Database records.
The first operational break into Enigma when the team working under Dilly Knox, with the mathematicians John Jeffreys, Peter Twinn and Alan Turing, unravelled the German Army administrative key that became known at Bletchley Park as The Green, encouraged by this success, the codebreakers later crack the Red key used by the Luftwaffe
Role range: 1939-1945
The first operational break into Enigma when the team working under Dilly Knox, with the mathematicians John Jeffreys, Peter Twinn and Alan Turing, unravelled the German Army administrative key that became known at Bletchley Park as The Green, encouraged by this success, the codebreakers later crack the Red key used by the Luftwaffe
Role range: 1939-1945
These dates and descriptions come from the historical_events database. Exact duplicate records have been collapsed. Names are grouped by the country, Name 2 and Name 1 fields; records with missing Name 2 cannot be reliably assigned to an individual biography. Check the underlying sources before formal citation.