1. Preheat oven to 370°F (190°C).
2. Remove giblets from a 4.5kg turkey then place in a large roasting tin. Rub the butter all over the skin of the turkey.
3. Season well with ground black pepper. Lay the bacon rashers over the turkey overlapping slightly. Cover both legs and breasts. Wrap loosely in foil creating a tent for the turkey. Cook for 1 hour.
4. Remove from oven, baste with any juices, recover and return to oven for 1 hour. Baste again. Cook for a third hour. Discard the foil, put the bacon to one side, baste well and cook uncovered for final 30 minutes to brown.
6. When done, place on a warm serving plate and cover with foil. Allow the meat to rest for 45 minutes while you make the gravy, then serve.