Bring to the boil. Once the water is boiling turn the heat down to a simmer.
Leave to simmer gently for around 20 minutes, until the liquid has started to thicken a little.
We then strained the liquid into a bowl through a sieve. The liquid was an amazing pink colour, whilst the remains of the rhubarb, perhaps I'll call it the pulp - stayed in a nice big clump... what to do with that!? Keep reading...
When the syrup was cool we put it into a mason jar and kept it in the fridge! For about 250ml soda (in my new favourite super cute coca-cola glasses) we put in 2 tablespoons of syrup, but it is really to taste - I have a feeling Jonathan put in more to get an even bigger rhubarb flavour :-P