Pre-heat your oven to 220ºC/200ºC fan.
Lightly grease a baking tray with butter (or use a non-stick baking mat and then this isn't necessary).
Put the self-raising flour (250g) into a large bowl. Cut the butter (50g) into cubes and add it to the flour. Rub together the flour and butter using your fingertips until it is the consistency of breadcrumbs.
Finely grate the zest of half a lemon and add it to the flour and butter mixture. Add the caster sugar (30g), baking powder (½ tsp) and salt (¼ tsp) and mix to ensure they're evenly distributed.
Make a well in the centre and add the gin (140ml) - I like to keep a tablespoon or two back to add at the end to help collect up any stray bits of flour. With as little action as possible mix the gin into the dry ingredients using your hands until the dough has come together. If there's any bits of flour left at the bottom add a touch more gin to help collect it up.
Place the dough onto a work surface and pat it into a flat circle about 1½ inches thick (don't use a rolling pin). Use a sharp knife to cut it into 6 wedges (you can also use a round cutter to make round scones if you prefer).
Move the scone wedges onto your prepared baking tray and bake for 12-15 minutes until the scones sound hollow when tapped on the bottom.
Once cooked, remove them from the oven and move them onto a cooling rack to cool completely.
Once the scones have cooled, make your icing. Place your icing sugar (50g) into a bowl and add 1 tsp of cold water. Mix until fully combined. You’ll find that your icing is quite thick and you want it to be just runny so that if you dip a spoon in and hold it up it drips off very slowly (if it’s too quick then it’ll run off and you won’t be left with any icing on the scones). Keep adding and mixing water a drop at a time until you reach the desired consistency. If you accidentally add a little too much, simply add a little more icing sugar. Once your icing is the right consistency, dip in a spoon and use this to drizzle the icing over the scones.