Make the marinade and sauce: put all the ingredients in a blender and whizz until smooth. Set aside half the mixture for the sauce and keep chilled in the fridge until needed.

Trim any excess fat from the chicken. Starting at the neck end, carefully lift the skin from the chicken, being careful not to tear it. Transfer to a large, non-metallic bowl and pour the marinade under the skin and over the chicken, so that its well coated. Cover with cling film and refrigerate for at least 4 hours or preferably overnight.

Preheat the oven to 200°C / 180°C (fan oven) / 395°F / Gas Mark 6. Lift the chicken from the bowl, scraping off any excess marinade, and transfer to a large roasting tin. Mist with cooking spray and season well. Roast for 1 hour 15 minutes, basting after 30 minutes, until cooked through. Remove from the oven and rest for 20 minutes before carving.