"Turning a blind eye" - generally ignoring facts or the reality of the situation - is a phrase that stems from the actions of arguably Britain's greatest naval hero, Admiral Horatio Lord Nelson, and is also referred to as "Nelsonian Blindness".
Admiral Nelson was a successful naval commander but had lost his right arm and the sight in one eye in battles at sea. Despite his injuries, Nelson continued his command of British naval warships in several significant engagements. At the Battle of Copenhagen in 1801, Nelson and a fleet of British ships encountered heavy resistance, and more powerful fire from the Danish fleet than had been anticipated. The commander of the British fleet, seeing they were overwhelmed, sent a signal, ordering Nelson to withdraw. Having been informed by the signal lieutenant of the signal to stand down, Nelson held up the telescope to his blind eye saying “I really do not see the signal”, and continued his attack. The battle resulted in both the Danish and British fleets suffering heavy damages, but Nelson’s perseverance helped to secure a truce with the Danish Crown Prince Frederick.
Nelson went on to command HMS Victory and despite being outnumbered, to defeat a combined French and Spanish fleet at the Battle of Trafalgar on 21 October 1805. It was his greatest victory, and his last, as Nelson was shot by a sharpshooter, and died from his injuries.
Rather than be buried at sea, he was brought back to London in a cask of brandy, tied to the mast of his ship; his body lay in state for 3 days at the Painted Hall in Greenwich, before being transported upriver on Charles II’s state barge, resting overnight at the Admiralty on Whitehall. It was then processed through the streets, accompanied by more than 10,000 soldiers for a state funeral at St Paul’s Cathedral where his coffin rests today.