Cut the top fourth off the loaf of bread. Hollow out the bread leaving a 1-inch shell. Slice the removed bread into cubes and save for dipping.
In a large bowl, beat cream cheese until fluffy. Add the sour cream, cheddar cheese and Worcestershire sauce until blended; stir in bacon and onions.
Spoon the mixture into the hollowed out bread. into bread shell. Wrap the bread in heavy duty foil and bake for 1 hour or until heated through. Unwrap and give the dip a stir if needed. Serve with crackers and reserved bread cubes.