Start off by preheating your oven to 200 degrees Celsius and then run the fishes under cold water, rubbing all over to remove any slime.

Place all the ingredients for the rub, including a few good twists of salt and pepper, into a pestle and mortar and pound everything together well until the mustard seeds and chillies have broken down.

Using a sharp knife, make three or four cuts along each side of the fishes. The cut should be deep enough to pierce both the skin and penetrate into the flesh below.

Work the rub into each side of the fishes and into the cavity where it was gutted. Cut the lemon into thin slices and stuff the cavities with lemon slices before arranging the fishes on a baking tray.

Drizzle with a little olive oil and place into the preheated oven. Roast for 30 to 40 minutes, turning once during cooking and draining off liquid which has accumulated in the pan; this will help the skin stay crisp.

Serve with accompaniments of your choosing - potatoes, salad, steamed vegetables etc.