1.Preheat the oven to 220C/gas mark 7
2.Roast for 30 minutes at 220C/gas mark 7 to start the crackling process
3.Now turn the oven down to 140C / gas mark 1 and cook for 3.5 hours.
4.Cover with tin foil whilst cooking but take it off for the last 45 minutes to help with the crackling.
5.Remove from the oven, cover with foil and rest for 30 minutes
Please Note, the above is only a guide and ovens may vary in temperature.