A prepared French fleet would still face overwhelming force

What losses might have followed if the French fleet had expected the Royal Navy and fought back at Mers-el-Kebir?

The counterfactual expects losses on both sides, with the outcome depending heavily on the French position, British carrier aviation, and the rules of engagement.

The counterfactual becomes more complicated if the French ships are at sea and ready to fight. There would likely be British as well as French losses, although no precise figure is offered. Force H had been assembled with substantial superiority and included an aircraft carrier, giving the British more than a surface-gunnery option. The result would turn on deployment and rules of engagement as much as on the nominal strength of the ships.