Place the stock in a large saucepan and heat gently. Wash and dry the prawns.
Heat the olive oil in a large paella pan. Cook the garlic until it turns golden, add the prawns and fry for 2 minutes. Remove from the pan. Add the chicken and pork. Season to taste with salt and pepper. Add the diced tomatoes.
Add the rice and stir well until the grains are transparent. Add the stock and bring to simmering point. Add salt and the saffron and paprika, cover and cook for 10 minutes, then lower the heat, add the prawns and cook for a further 10 minutes.