The Weider History Group replied to a query, “Did Churchill allow Coventry to be burned to protect his secret intelligence?” Their answer was somewhat equivocal:
There certainly have been a variety of different accounts, even supposedly by eyewitnesses, that contradict each other as to how much Winston Churchill had learned from the Boniface (later Ultra) decoders as to the main target for the German “Moonlight Sonata” air raid on the Midlands in November 1940, and when did he ascertain it. Whether he mistook it for a feint, with London the actual target, of whether he knew of Coventry and left it to its fate rather than compromise Britain’s ability to crack the German Enigma codes seems to depend on one’s feelings toward Churchill.…
Not quite robust enough!
Whether you accept that Churchill “let Coventry burn” does not depend on your “feelings toward Churchill.” It depends on whether you know the facts.
The facts are that Churchill, leaving for the country that night, read a despatch in his car predicting a heavy raid upon London, not Coventry. Declaring he would not spend the night in safety while the capital was under attack, he turned his car around and went back to Downing Street. Also, when the truth was known, RAF fighters were mustered to defend Coventry, but it was too little and too late.