Steam the clams
Heat a large pot or Dutch oven over medium-high heat. Bring 3 cups of water to the boil, add the clams and cover the pot. Cook until the clams have all opened, about 8 minutes.
Chop the clams
Set a fine mesh strainer over a medium bowl. Pour the clams through the strainer and reserve the cooking liquid. Remove the meat from the shells. Chop the clams and set aside.
Cook the bacon
Return the pot to medium heat and add the bacon. Cook the bacon until the fat is rendered and the bacon is crispy, about 5 minutes.
Set bacon aside
Use a slotted spoon to remove the bacon, reserving as much fat in the pan as possible.
Return the pan to medium heat then add the butter and allow to melt then add the onion and celery. Sauté, stirring occasionally, until the onion is soft and opaque, about 5 minutes.
Add the garlic and cook for an additional minute. Stir in the flour and cook for 2 minutes, until the flour is pale brown.
Add the chicken stock, 2½ cups of the reserved cooking liquid, bay leaves, potatoes, and thyme. Stir to combine and bring to a simmer for about 30 minutes, continuing to stir occasionally, until the potatoes are tender.
Stir in the cream and continue to simmer for an additional 10 minutes.
Add bacon and clams
Discard the bay leaves and sprig of thyme. Add the bacon and chopped clams to the broth, then stir in the Worcestershire and season to taste with salt and black pepper.
To serve, ladle the clam chowder into bowls, garnish with chives. Serve hot with oyster crackers on the side.