Place the bacon in a cold, large skillet. Cook over medium heat until crisp and brown, about 5 minutes. Transfer the bacon to paper towels to drain and cool. Finely chop the bacon.

In a medium, heavy-bottomed saucepan, bring the ale to a bare simmer over medium heat. In a medium bowl, toss the cheese with the flour. Gradually stir the cheese into the saucepan, stirring the first batch until melted before adding another. In a small bowl, dissolve the mustard in the Worcestershire sauce. Stir into the fondue, along with the chopped bacon. Allow the fondue to come to a bare simmer, but do not boil. Season generously with the pepper. Transfer to a cheese fondue pot and keep warm over a fondue burner. Serve immediately, with dipping ingredients of your choice.