Put the fish in a pan, add the milk and poach for 4 minutes. Drain and flake the fish, reserving the milk. Set aside.
Fry the bacon until crisp; chop into small pieces and set aside.
Put the potatoes in a pan of cold water, bring to the boil, then simmer until soft, about 15 minutes. Drain, return to the pan and leave to steam dry for 10 minutes. Mix in the butter and a good spl