Spray a frying pan with low-calorie cooking spray and set the pan on a medium heat. Add the diced pork and season with a little salt and pepper. Fry until lightly browned on all sides.
Add the onion, garlic, chilli and the pork to the slow cooker pot. In a jug combine the stock pot and water along with the tomato puree, Henderson’s relish, cider vinegar, sweetener, cumin, mustard powder and chilli flakes. Stir to combine.
Pour the stock into the slow cooker and give the pot a stir. Cover with the lid and set the slow cooker to high.
Cook for 3 hours then add the sliced red pepper. Cover with the lid and cook for a further hour.
Sprinkle with coriander, if using, and serve with your choice of accompaniment.