Step 1

For the dressing, whisk the tomato, garlic, lemon juice and olive oil until thickened, then season to taste with sea salt and freshly ground black pepper.

Step 2

Remove the heads from the prawns, butterfly along the back and devein.

Step 3

Cut the scampi in half lengthways, then remove the vein and clean by rinsing under cold water. Cut the tuna into four small steaks. Coat everything with olive oil and scatter with sea salt.

Step 4

Heat a lightly oiled chargrill or barbecue to medium-high heat. When hot, place the prawns and scampi on the grill (in batches if necessary), cut-side down. Cook on one side for 1-2 minutes until well-coloured, then turn to cook briefly on the other side for 30-60 seconds or until just cooked through. Cook the tuna for 1-2 minutes on one side, rotating to create criss-cross grill marks. Turn and cook on the other side for a further minute.

Step 5

Arrange all the seafood casually on a large serving platter. Spoon over the dressing and scatter with parsley.

Step 6

Serve with lemon wedges.