Soak the skewers in cold water for at least an hour. This helps prevent them from burning, but not altogether.
Place all the marinade ingredients in a large bowl and mix well. Add the lamb and toss to combine. Cover and set aside while you make the green yoghurt sauce.
Soak the saffron in 1 tablespoon of boiling water. Heat a frying pan over a low heat, add the oil and onion and cook until soft, but not coloured. Cool, then place, in a food processor with the remaining ingredients (including saffron liquid) and process until smooth. Season with salt and freshly ground black pepper. Spoon into a small serving bowl. If you can, make the sauce and leave to sit for about half an hour to allow flavours to mingle. This is a thick sauce, so add more yoghurt if you prefer it thinner.
Heat the barbecue to medium-high or use a large frying pan. Lightly oil.
Thread 3 pieces of lamb on to each of the soaked skewers and place on the barbecue. Cook for 6-7 minutes, turning as they cook to brown and cook evenly.
Serve lamb skewers with the bowl of green yoghurt sauce and steamed green vegetables.
Chef's tip
Try using rosemary branches as skewers. The rosemary imparts flavour as the meat cooks. Strip most of the leaves off, leaving just a few at the top. Older rosemary sticks are easier to skewer with.