Preheat the oven to 200 c (gas mark 6). Put the lamb into a saucepan with the tomato juice, stock, vegetables, salt and pepper and mixed herbs. Bring to the boil and stir. Cover the pan and allow it to simmer for 15 minutes. The spoon the mixture into an ovenproof dish. Mash the potato and place on top of the meat and sprinkle with a little paprika. Bake in the oven for 15 minutes, or until the top is golden brown.
To make this into a meal for 2 lunches, try adding peas and sweetcorn and a few cherry tomatoes to bulk it out a little bit more!