Heat the oil in a wok over a high heat. Add the garlic and chillies to the wok and stir-fry until the garlic is just golden. Add the pork, pepper, fish sauce and sugar, stirring constantly.
Stir in the bamboo shoots, if using, with the onion, red pepper and stock. Cook for 5 minutes. Stir in the basil leaves and cook for 1 minute more.
Garnish with basil leaves and large slices of red chilli, then serve immediately with rice, if liked.