Cut half a lemon into thin slices and set aside as a garnish.

Place the second half in a blender, skin, pips and all (although if the pith is very thick, slice it off with a sharp knife and discard). Squeeze in the juice from the remaining lemons.

Add the sugar and 200ml of water and blitz to a puree, before straining through a coarse sieve.

Pour into a jug and top up with either 400ml of water or soda, before garnishing with the lemon slices and sprigs of mint. Add a touch more sugar if you prefer it sweeter!