Heat oil in large, lidded pan.

Add onion and carrot, fry over medium heat for 5 mins until soft

Add mince, fry until brown

Add tomatoes, puree, stock, bay and thyme.

Simmer for 30 mins

Add ketchup and worcestershire sauce

boil until correct consistancy

In a seperate pan, fry leeks in butter until soft

Place meat in an oven proof dish, lay the leeks on the meat,

Place mashed potato on top of leeks and smooth the top

Cook in oven, gas mark 5 for 30-40 mins until top is crisp and brown