- Preheat the oven to 160°C/gas mark 3.
- Using a sharp knife, make 36 incisions in the meaty end of the leg. Fill the holes with the garlic cloves, anchovies and rosemary sprigs paced out equally.
- Place the meat on a roasting tray, season with sea salt and pepper and drizzle with olive oil. Lightly rub the seasoning into the flesh to coat the leg.
- Roast the leg in the oven for an hour, or until the core temperature reaches 58°C. Put the lamb to one side to rest in a warm place for about 20 minutes. Carve and serve.