Toast bread until lightly browned. Let cool and process in a mini chopper or blender.
Coarsely chop the fish. This can be done in the food processor, but with care or the fish will quickly turn into paste.
Fold the fish together with the breadcrumbs.
Add Worcestershire sauce, mustard, egg, celery, lemon peel, mayonnaise, thyme, salt and pepper.
Fold together gently until well blended.
Form into 8 cakes and chill. This can be made up to 12 hours in advance.
Preheat the oven to 325° F.
Place the oil in a large non-stick skillet over high heat until the oil is almost smoking.
Place cakes in the hot oil and cook over medium-high heat for about three minutes until brown.
Turn and cook for about 2 minutes.
Place in hot oven. Cook for another 9 to 10 minutes.
