To make the marinade, put the spices, salt, ginger, garlic and onion in a blender and blitz until as smooth as possible. Turn the paste out into a large bowl, then stir in the yoghurt and lemon juice. Stir in the food colouring paste, if using. (Ideally, use colouring paste designed for cake decorating, as liquid food colouring won’t tint the marinade sufficiently.)
Remove the skin from the partridges and cut each bird in half, first along and through the breastbone and then the spine. Score the thighs and breasts lightly several times with a sharp knife. Drop the halved partridges into the tandoori marinade and turn them over until all are well coated. Cover the bowl with clingfilm and leave to marinate in the fridge for at least 3 hours.
About 45 minutes before serving, light a small charcoal barbecue and let the flames die down to hot coals. Take the tandoori pieces out of the marinade and tap off the excess. Put the birds on the barbecue and cook for 6–8 minutes on each side, or until the meat is nicely charred but tender and cooked through (take care not to overcook them so that they become dry). Serve with lemon wedges, iceberg lettuce, red onion and naan bread. Tandoori partridge