Did Churchill deliberately sacrifice Coventry?

There is a controversial, but widely accepted, belief that on Nov. 14, 1940 Winston Churchill decided not to have the RAF defend Coventry against a major German bombing raid (500 bombers), despite having been informed of the target by Ultra (decrypted Enigma messages), in order to avoid alerting the Germans to the fact that their code was broken.

The Bletchley Park Trust says that this was not so.

There are numerous examples of Churchill not hesitating to suppress valuable intelligence derived from Bletchley Park decrypts, when there was no other plausible source for that Intelligence, in order to preserve the vital secret that BLETCHLEY PARK was breaking the major German codes such as Enigma. The raid on Coventry on 14th November 1940 (Operation Moonlight Sonata) was NOT one of them.