Napoleonic brigs as frigate substitutes

How many brigs did the Royal Navy have in the Napoleonic Wars, and how effective were they?

Using a Mediterranean example, the answer estimates about twenty brigs and places them in the working fleet as convoy escorts, inshore support, and occasional frigate substitutes.

The answer places brigs below the frigate force but firmly inside the practical working fleet. They filled escort and inshore-squadron gaps when frigates were scarce, and could fight comparable small vessels without being expected to overpower larger warships. Their importance therefore came from expanding the navy's routine presence and convoy capacity.