Stir in the sugar, then gradually add just enough milk to make a soft, but not sticky dough, stirring it in with a round-bladed knife. Turn the dough onto a lightly floured surface, flour your hands a little, then knead the dough lightly for a few moments.
Using a lightly floured rolling pin, roll out the dough to about 2.5cm (1in) thick, then use a 5cm (2in) plain or fluted cutter to stamp out rounds. Gather any trimmings together, re-roll and cut out more scones.
Arrange the scones on the baking sheet. Brush the surface with a little milk, then bake for 18-20 minutes towards the top of the oven, until well risen and golden brown. Cool for a few moments and then transfer to a cooling rack. Serve warm, with clotted cream and strawberry jam.