The day before, make up the marinade then prick the turkey drumsticks all over. Use 1/3 of the marinade to brush over the turkey. Cover with cling film and leave in the fridge overnight.
The next morning remove the drumsticks from the fridge, season with salt and pepper and leave to come to room temperature for 30 minutes.
Turn on the barbeque, using only the front gas jets. Heat to 120°C (250° F), checking the temperature with a thermometer.
Place the turkey on the coolest part of the barbecue and cover with the lid. Cook for 30 minutes, then brush with marinade
Continue cooking over that very low heat, brushing the drumsticks every 30 minutes or so. Check they are ready - you should be able to push your finger through with little resistance after 4 hours. If you can leave it for 6-7 hours even better.
© Phil Vickery