Preheat the oven to 220°C (200°C fan).

Sift the self-raising flour and baking powder together in a large mixing bowl.

Incorporate the cold, cubed butter into the flour mixture using your fingertips until it resembles fine breadcrumbs.

Stir in the caster sugar and a pinch of salt, mixing evenly.

Create a well in the center and gently pour in the buttermilk, mixing until a soft dough forms without overworking it.

Turn the dough onto a lightly floured surface and gently knead it just until smooth.

Pat the dough down to about 2.5cm thick and cut out rounds with a 6cm cutter.

Place the rounds on a parchment-lined baking tray and brush the tops with milk.

Bake in the preheated oven for 12-15 minutes, or until risen and golden brown.

Cool the scones slightly on a wire rack before serving.