Heat the oil in a large pan, crumble in the mince and stir to coat in the oil. Cook for 15 mins, stirring occasionally until the mince is browned and the fat from the meat has been released. Stir in the onions and carrots, and cook for 10 mins until they soften and start to turn brown.

Sprinkle over the flour and cook for a further 2 mins. Stir in the ketchup or tomato purée, if using, splash in the Worcestershire sauce, then gradually stir in the stock. Season and leave to simmer gently for 45-50 mins until you have tender mince in a rich gravy.

While the mince is cooking make the tatties. Tip the potatoes into a pan and cover in salted cold water, bring to the boil and simmer for about 15 mins until tender. Drain well, then allow to steam-dry for a few mins. Mash well with the milk and butter, then season with salt and pepper. Serve the stewed mince spooned over the tatties.