Add the limes, elderflowers, and water to a big pan.

Pop it onto the hob on a medium heat and bring it to the boil. As soon as it begins to boil, turn it off, pop a lid on and let it steep overnight.

The next day, strain it using a coffee filter, muslin, or jelly bag.

Put the liquid in a clean pan, add the sugar and citric acid and bring it to the boil, stirring to dissolve the sugar.

While this is happening, make sure you have sufficient jars/bottles clean and sterlised, ready to fill.

When the liquid is boiling let it simmer for five minutes and skim off any foam.

After five minutes, decant it into the bottles, still warm, and seal.

Once cooled, this will keep for weeks on end! Enjoy drizzled onto syrup, added to your favourite G&T, or with soda water and a slice of lime.