Cut the end off the potato and spiralize (or chop into thin matchsticks if you haven't got a spiralizer).
Heat the oil to 170°C/350°F and fry the potatoes in batches for around 3 minutes (or until the chips are brown). Be careful of the oil as the potatoes can still be quite wet - dry them with a towel beforehand and if the oil starts to foam take them out with a pair of tongs and wait for it to die down.
When all the fries are cooked, mix together the spices and sprinkle over the top. Serve with mayo and ketchup.