Thaw shrimp, if frozen. Peel and devein shrimp, leaving tails intact. Rinse shrimp; pat dry with paper towels. Set aside.
In a large skillet cook and stir shrimp, leek, basil, and garlic in hot oil over medium heat for 2 to 4 minutes or until shrimp are opaque. Carefully add sherry, lemon juice, salt, and pepper to skillet. Cook and stir just until heated through. Stir in parsley.