Heat the oil in a large frying pan over high heat.

Season the lamb shanks with salt and pepper, then brown on all sides for about 10 minutes.

Remove the lamb from the pan and place it in the slow cooker.

Add the onion and carrots to the frying pan and cook for 5 minutes, stirring often until softened. Then add the garlic and cook for a further minute while stirring.

Add the red wine, stock, thyme, tomato puree, sugar, and bay leaves to the frying pan.

Bring to a simmer, then turn off the heat and pour the sauce over the lamb shanks in the slow cooker.

Place the lid on and cook on low for 7-8 hours until the lamb is very tender.

Once cooked, remove the lamb shanks from the slow cooker. Discard bay leaves and stir the redcurrant jelly into the sauce.

To thicken the sauce, slowly pour in the cornflour slurry while stirring with a whisk until thickened to your liking.