2-3 unwaxed lemons, halve and juice them and place the skins in a 1-2 pint non-metallic jug, together with about 1 desert-spoon of sugar per lemon, juice goes in the fridge for the moment.

Squash the skins about a bit with the end of a rolling pin, then scald with boiling water (about half-fill the jug) and keep mashing for a while, remove rolling pin and set jug aside to go cold.

Don't hurry the cooling, this is where the flavour is extracted, I sometimes reheat in the microwave, but don't let it boil. If using Epsom Salts for extra bitterness this is the time, but lightly does it as the laxative effects could be unwelcome. About a rounded teaspoon maximum for this quantity.

When the skins jug is cold, strain off the skins and stir in the juice, then refrigerate. Consume within 48 hours. This is a still drink, but soda water or tonic will fizz it up if required.

This also works well with limes, OK with grapefruit, but not really with oranges (IMO).