Place the fish on a plate and season with salt and pepper. Cover with cling film and chill for 10 minutes while you make the batter.

Sift the flour into a bowl and add the baking powder, cayenne pepper, a decent pinch of salt and a little black pepper. Add the oil and ginger beer, stirring as you do so, until the mixture has the consistency of thick double cream. Leave to stand for 30 minutes.

Pour a one-third depth of oil in a large, deep saucepan. Place over a medium heat until the temperature reaches 160°C, or a dollop of batter spooned into the oil rises immediately to the surface and bubbles form around the outside.

Place a handful of flour on a plate, season with salt and pepper and coat the fish in it, shaking off any excess. Give the batter a stir, dip the fish in it, allowing any excess to drip off, then fry for 3–5 minutes (depending on the thickness of the fish), until the batter is dark golden and crisp. Lift out with a slotted spoon, drain on kitchen paper and season with a pinch of salt. Keep warm while you cook the remaining fish in the same way.

Serve the fish warm with the Chilli Mushy Peas on the side, if using