1. Joint the chicken into 8 pieces. Put the chicken joints in a bowl and add enough milk to cover. Cover securely with cling film and soak for 8-12 hours.
2. With the slotted spoon, transfer the chicken joints to a dish. Discard the milk.
3. Pour vegetable oil into the frying pan to make a 2cm deep layer. Heat the oil over moderate heat to 180°C on the deep-fat thermometer.
4. Put the seasoned flour in the shallow dish. Dip the chicken joints in the flour and pat off the excess with your hands to obtain an even coating.
Note: To coat the chicken quickly, drop the joints into a plastic bag, add the seasoned flour, twist the bag closed and shake about 30 seconds.
5. Gently add the chicken joints to the pan, skin side down, taking care as the chicken may sputter. Fry until brown, 3-5 minutes.
6. Turn the chicken joints over and reduce the heat to low.
7. Continue frying until the chicken is brown and tender when pierced with the 2-pronged fork, 20-25 minutes. If some pieces cook before others, remove them and keep warm.
8. Transfer the chicken to a dish lined with kitchen paper and keep warm. Take Care! If keeping the chicken warm in a low oven, do not cover it or the crisp coating will soften.
Make the Gravy
1. Discard all but about 2tbsp of the fat from the frying pan. Sprinkle in the flour.
2.Cook, stirring with the large metal spoon, until browned, 2-3 minutes.
3. Whisk in the milk and simmer until thickened, about 2 minutes. Season the gravy to taste and strain into a gravy boat.