The signal flown from HMS Victory just before sailing into battle off Cape Trafalgar, Spain. Today is the 201st anniversary of the battle of Trafalgar. Admiral Lord Nelson led the Royal Navy fleet against the combined French and Spanish fleet. His fleet cut the line of battle in two places won a stunning victory against a numerically superior force. Lord Nelson lost his life in the battle.
An excellent history of the battle and of the Royal Navy during that time period can be found here.
UPDATE: On a completely unrelated note, but weirdly appropriate nonetheless, Britain appears to be ready to start using prison ships to house prisoners once again. Everything old is new again.