Skin the tomatoes by cutting a shallow cross into the bottom of each, then plunge them into boiling water for about 30 seconds.
Carefully transfer the tomatoes into a bowl of iced water. The skins should then peel off easily.
Cut each tomato into quarters, scoop out the seeds and place into a sieve over a bowl.
Press the seeds and pulp through the sieve to release the juice into a bowl. Put the tomato quarters into a separate bowl.
Cut each of the skinned red and yellow peppers into eight pieces and add to the tomato quarters.
Add the chilli, capers and olives.
Tear the ciabatta into large chunks and place into a separate bowl.
Add the vinegar, garlic and oil to the sieved tomato juice. Season, to taste, with salt and freshly ground black pepper and whisk well to combine.
Pour the tomato juice mixture over the ciabatta pieces and leave to soak for an hour.
Add the tomato quarters and peppers mixture to the soaked ciabatta and garnish with the basil leaves.
Serve in a large salad bowl at the table.