Wash shrimp and leave in the shell. Melt butter in a large frying pan and stir in the garlic, Worcestershire sauce and seasonings. Add shrimp and shake the pan to immerse the shrimp in butter, then sauté over medium-high heat for 4 to 5 minutes until they turn pink. Next, pour in the beer and stir for a further minute, then remove from the heat. Shell and devein the shrimp and arrange on a bed of rice. Pour the pan juices on top and garnish with chopped scallion.