Preheat the oven to 230°C / 450°F / Gas mark 8.
Coat the butter all over the poussins using your hands, season inside and out with salt and pepper then layer the bacon over each one criss-crossing over to cover evenly.
Sit the poussins in a roasting tin and cook for 40 minutes until the birds are golden and the bacon is crisp.
Remove from the tin, leave to rest and set the tin aside.
To make the gravy, (this step should be done only just before you are ready to sit down), place the tin on a medium heat, then stir in the flour and the Worcestershire sauce.
Let it bubble together, then stir in the vegetable stock.
Bring the gravy to the boil, taste for seasoning, adding more Worcestershire sauce if needed, then pour into a pre-warmed gravy jug.
Serve straight away.