Prepare the stock in a large pan using your favourite chicken stock cubes, boiling water and 1 tablespoon of the curry powder. Add the potatoes and the carrots to the stock. Bring to the boil, then lower heat and simmer for 10 minutes, till the potatoes and carrots soften.
In a separate pan add the olive oil and gently fry the garlic, chicken and onions, adding the remaining spices until chicken is cooked and onions are soft.
Add the chicken mix to the stock along with the chopped tomatoes, stirring together. Gently simmer, adding the mushrooms after 20 minutes. Add more spice to taste if preferred. Simmer for a further 20 minutes.