First make the marinade by putting all of the ingredients in to food chopper or pestle and mortar and blitz / pound until a thick paste is created. If it is too thick you can add a little water at a time to loosen it until the desired consistency.

With the lamb score the top over the skin about half a centimeter down and about an inch apart. Rub the baste all over the lamb and then refrigerate for about 2 hours or over night if you have time.

Remove from the fridge half an hour before cooking. Pre-heat the oven to 200C.

Place the lamb in the oven on a roasting tray and then cook for 30 minutes of which then turn the oven down to 160C and cook for a further 1 hour and 10 minutes.

When cooked leave to rest in the pan covered in foil for 20 minutes.

Carve when ready and serve with crispy roast potatoes, your favourite vegetables and gravy.