1. In water, wash lemon. Pat dry. Using a zester, grate the zest from the lemon.
2. Take a jug, put in zest and sugar. Boil and add 1/4 pint of the water.
3. Using a long spoon, stir until sugar has dissolved. Cover jug and allow to infuse until the water is quite cold.
4. Pour in remaining 1/2 pint cold water, and finally squeeze in the lemon juice.
5. Through a seive, strain into a glass jug.
6. Serve chilled.