Turning a blind eye is an idiom describing the ignoring of undesirable information.
[1] The phrase to turn a blind eye is often associated with Vice Admiral Horatio Nelson at the Battle of Copenhagen in 1801.
An orchestrated version of what actually happened gives the story that during the battle, Admiral Sir Hyde Parker, in overall command of the British forces, sent a signal to Nelson's forces ordering them to discontinue the action.
[2][3] The frigates supporting the line of battle ships did break off, in one case suffering severe losses in the retreat.
Sir Hyde Parker was recalled in disgrace and Nelson was appointed Commander-in-Chief of the fleet following the battle.