2. Finely chop the whole garlic head.

3. Combine with the remaining marinade ingredients.

4. Place the lamb in a large, deep container or baking dish and pour in the marinade.

5. Turn the lamb in the marinade so that it is coated all over.

6. Cover and refrigerate overnight.

7. Using a mortar and pestle, crush the ingredients for the dry rub all together until they are pastelike in consistency.

8. Remove the lamb from the marinade and discard the marinade.

9. Make 10-15 small incisions all over its surface using a small, sharp paring knife.

10. Stuff each of these little holes with the dry rub and rub whatever is left over the surface of the lamb.

11. Season well with salt and pepper and rub the lamb with about 2 tablespoons of olive oil.

12. Preheat the oven to 375°F (190°C).

13. Place the potatoes in a large roasting pan and toss with the lemon juice, garlic, olive oil and oregano.

14. Season well with salt and pepper.

15. Place the lamb over the potatoes.

16. Roast, frequently basting both the lamb and the potatoes with the pan juices for about 1 hour and 30 minutes, for a well-done leg.

17. Add a little water to the pan during baking if necessary to keep the pan juices from drying out.

18. Remove the lamb from the oven and let rest for about 10 minutes before carving.

19. Keep the potatoes in the turned off oven until ready to serve.