Preheat the oven to 200C/180C (Fan)/Gas 6. Cut the potatoes into chunky chip-sized wedges and add to a saucepan. Pour over boiling water from a kettle to cover and boil for 5 minutes. Drain.
Pour the oil onto a baking tray. Add the drained chips and and toss until the chips are evenly coated. Spread the chips out into a single layer, season with salt and freshly ground black pepper, then cook for 20-25 minutes. Check after 10 minutes, shaking and turning occasionally, until golden-brown and crisp.