If Nelson loses at Trafalgar

What happens if Nelson fails at Trafalgar?

A French and Spanish victory would matter, but their damaged fleet would still face other Royal Navy forces and further battles before it could exploit the result.

A defeat for Nelson would matter without causing an automatic British strategic collapse. The combined fleet would have greater confidence and might retain more ships, but victory would still leave it damaged. Other British fleets remained between it and any larger objective. The French and Spanish would therefore have to win another battle, and perhaps another after that, before converting Trafalgar into command of the sea. The wider forces and campaigns surrounding a famous battle still shape what its result can achieve.