In a medium bowl, combine Worcestershire sauce, vinegar, soy sauce, chilli powder, garlic and hot pepper sauce. Place chicken in sauce, and turn once to coat. Marinate for 30 minutes at room temperature, or cover and refrigerate for several hours.
Heat oil in a large frying pan over high heat. Add chicken strips and stir fry for 5 minutes. Add the onion and capsicum and cook for 3 minutes. Remove from heat, and sprinkle with lemon juice.
Used different ingredients.
This is the best fajitas recipe I have found. I substituted about 1/2 T of lime (instead of the lemon) and added it to the marinade. I also let the meat simmer in the juices - this makes sure that it won't be dry but juicy instead. - 18 Jul 2008