Melt margarine in a large frying pan. Fry chicken joints slowly for 20 to 25 minutes, turning occasionally until golden brown and tender.
Remove joints and place on a warm serving dish.
Add remaining flour to fat in pan and cook for 2 minutes. Dissolve stock cube in boiling water and add to pan. Bring to boil, stirring, and cook for 2 minutes. Add milk and salt and pepper to taste.
Peel cucumber, cut into small dice and add to sauce; reheat and pour over chicken. If liked, serve with grilled, halved tomatoes.
Notes
I've presented the recipe as it was originally written, including Imperial measurements.