Set the oven to 200°C/400°F/Gas Mark 6. Pour the can of tomatoes and 300ml (½ pint) water into a pan, add the celery and onion and bring to the boil.
Reduce the heat and simmer for 5 mins.
Add the turkey to the pan and simmer for a further 10 mins, stirring occasionally.
If the mixture is very runny, increase the heat and boil off some of the excess liquid.
Remove the pan from the heat and stir in the peas, seasoning and Worcestershire sauce. Spoon into an ovenproof dish.
To make the mash, cook the potatoes and carrots in boiling water for about 15 mins or until tender, then drain well.
Return the veg to the pan, add the milk and mash until smooth. Season, then spoon on top of the base.
Bake the pie for 30-40 mins, or until the topping starts to turn golden.
Remove from the oven and serve immediately.