In a large Dutch oven or a heavy-based pot, melt the butter over medium heat.
Add the diced onions and sauté until soft and translucent.
Stir in the carrots, and celery, and sauté until they are tender and fragrant.
Add the garlic, salt, and freshly ground pepper, and cook for an additional minute, allowing the flavors to meld.
Sprinkle the flour over the vegetables and stir well to coat. Cook for a couple of minutes to cook off the raw flour taste.
Gradually pour in the chicken broth while stirring constantly to prevent lumps from forming.
Add the salt, freshly ground pepper, bay leaves, thyme, and Worcestershire sauce. Bring the mixture to a gentle simmer.
Add the double cream along with frozen peas and shredded chicken to the pot. Stir well to combine.
Allow the soup to simmer for about 15-20 minutes, allowing the flavors to develop and the chicken to heat through.