Scrub lemons well and pat dry to remove preservative wax. Peel off the rind avoiding bitter white pith.
Mix lemon peel, juice and vodka in large jar with 1 litre water.
Mix the sugar with 125ml water in a small pan and slowly bring to boil to dissolve sugar, allow to cool slightly and then add to the vodka jar.
Cover and set aside for 24 hours in a cool place.
Strain through muslin/cheesecloth or kitchen paper twice to ensure it is completely clear and pour into sterilised bottles.