I saw this on TV last night and then found it again at the Ace of Spades, (below).  The John Cunningham mentioned below was a prewar test pilot.  He was an advocate of airborne radar to target the German night bombing of England.  He flew an aircraft equipped with radar and was responsible for shooting down 19 German aircraft, a triple ace and then some. The cover story regarding carrots, was an attempt to disguise the fact that radar was responsible for German losses.

British gunners in WWII were able to locate and shoot down German planes at night due to significant advancements in radar technology. To help cover up their improvements on the technology, the British spread about an urban legend that said that they were able to increase the night vision of their pilots by having them consume large amounts of carrots. This propaganda campaign included stories about certain pilots like Lieutenant John “Cat Eyes” Cunningham who they said had exceptional night vision thanks to a habit of eating large amounts of carrots. This lie not only gave birth to an urban legend, but also caused many British people to start planting their own vegetable gardens, including planting and eating a large amount of carrots so that they’d be able to see better during blackouts.

Could it be that Bugs Bunny was part of the deception campaign?

As a kid of the 60’s I remember being told to eat my carrots in order to improve my night vision. This story is also an object lesson in how seemingly innocuous information becomes classified, a lesson Hillary ignored to her peril.

Both sides, Allies and Axis had radar.  Both sides used it to spot formations of aircraft and chart their progress.  Both sides used radar to vector fighter aircraft onto incoming bomber streams.

Both sides consumed carrots as part of a normal diet.  One side, the allies, heralded properties found in carrots as a panacea for increasing night vision.  Increased night vision could enable gunners to be more efficient in shooting down enemy aircraft. If the Axis air force accepted improved night vision as the source of their losses then increased consumption of carrots, to improve Axis pilot night vision was appropriate.

So the ability shrink a radar unit to the size capable of being fitted into a fighter aircraft and information that carrots had absolutely nothing to do with improved night vision became coequal in the secrecy game. Had the Axis rejected night vision and learned the truth about carrots they would have searched for another explanation. Had they found airborne radar and they could have developed radar jammers. Instead they got carrots.

So while there is nothing secret about carrots themselves, and the story regarding their ability to affect night vision is false.  The fact that a deception is taking place is a legitimate secret worthy of classification.