In a deep frying pan, heat the olive oil over medium-high heat. Lightly coat the prawns in flour. In batches, saute prawns in oil until golden brown; each batch should take approximately 2 minutes. Drain on paper towels.
Discard oil then add the wine, Worcestershire sauce, garlic, lemon juice and chicken stock to the frying pan. Cook over high heat until liquid has reduced by half, about 5 minutes. Stir in butter and season with salt and pepper to taste. Lower heat to medium, add prawns then cook until prawns are heated, about a minute. Sprinkle with parsley before serving.