Preheat the oven to 220C/200C Fan/Gas 7 and lightly grease a large baking tray.
Mix together the flour, baking powder and salt. Using your fingertips, rub the butter into the flour until the mixture resembles fine breadcrumbs.
Stir in the sugar. Add most of the milk and mix to form a soft and slightly sticky dough. If the dough is a little dry, add more of the milk until you have the correct consistency (you might not need all the milk).
Turn out onto a floured work surface and knead very lightly.
Pat out into a round about 2cm/¾in thick.
Use a 5cm/2in cutter to stamp out rounds and place on the baking tray. Lightly knead together any remaining dough and stamp out more scones to use it all up.
Brush the tops of the scones with beaten egg (try to avoid letting any egg run down the sides as this will affect how the scones rise).
Bake for 12–15 minutes, or until well risen and golden-brown.
Cool on a wire rack. Serve with jam and butter, or maybe some clotted cream.
