Put the flour, cornmeal, baking powder and salt in a bowl and mix with the beer and egg. Let rest for 20 minutes.
Heat the oil to 175 ° C.
Dry the potatoes well and fry them in the oil (note the temperature) until they are soft (no more bubbles appear), then pour them onto paper kitchen towels.
Dip the fish fillets individually in the batter, add them to the hot oil and deep-fry until golden (note the temperature).
Bake in the oven on the grid (so that the oil drips off) at 250 ° C (don`t forget the drip tray).
Fry the potatoes for another 1-2 minutes until crispy.
Serve with malt vinegar and salt. In England this dish is still wrapped in a newspaper in some shops.