1 Heat a large frying pan.
2 Add the vegetable oil, fry the onion until soft but not coloured.
3 Add the diced carrots, celery and potatoes and cook for further 5 minutes until softened.
4 Add the Worcester sauce, tomato puree and sugar and fry for another 2 minutes.
5. Add the stock or water and continue to simmer.
6 Add the corned beef and the peas.
7 Make sure all the ingredients are well covered, if not add a little more stock or water.
8 Continue to simmer, stirring occasionally until the carrots and potatoes are done and most of the liquid has been absorbed.
9 Sprinkle with parsley and leave to cool slightly.
10 Make the pastry by sieving the flour into a large mixing bow.
11 Rub the fats with the flour and salt together until they resemble breadcrumbs.
12 Add sufficient cold water and combine the pastry together.
13 Cover the pastry dough with cling film and allow to rest in the fridge for at least 20 minutes.
14 Roll out 2 thirds of the pastry and line a pie dish.
15 Roll out the remaining pastry and cover the top of the pie.
16 Dampen the edge of the pastry on the pie dish.
17 Pour in the cold corned beef mixture.
18 Cover the pie with the pastry lid.
19 Brush the top with egg wash or milk.
20 Prick with a fork.
21 Bake 1t 180 degrees centigrade/gas 4 for 35 - 40 minutes or until the pastry is golden brown.
22 Serve straight away with a good gravy.