What counts as losing command of the sea?

A loss of sea control requires a prior position of control, with a distinction between global command and a temporary local advantage. Caribbean force ratios changed as British and French squadrons arrived or departed. For Britain, preventing a French invasion of the home islands carried greater strategic weight than holding the largest fleet off a particular overseas possession. Byng's failure to relieve Minorca could therefore create a perception of lost command while the defeat of French invasion plans in 1759 demonstrated Britain's ability to defend its home waters. Wartime loss totals also require comparison with enemy losses and scrutiny for vessels counted more than once after capture and recapture.