Heat the olive oil in a frying pan and gently fry the onion and green peppers for 5 minutes, or until softened. Add the garlic and spring onions and fry for a further 5 minutes. Tip into a bowl.
Add the breadcrumbs, crabmeat, Worcestershire sauce, cayenne, parsley and beaten egg and season with a little salt. Mix well with a wooden spoon, or with your hands, until the mixture is evenly combined.
Divide the mixture into 4 equal pieces and shape each into a ball. Flatten into a burger shape.
Heat a very thin layer of sunflower oil in a large frying pan. Fry the burgers (if necessary in 2 batches) for 4–5 minutes on each side until golden. Serve the burgers on a bed of lettuce, topped with tomato relish, if liked.