This is a fungal disease that infects woody perennials, slowly killing the plant.
It presents itself as small coral-coloured pustules along the dead woody material, hence the common name coral spot.

The main symptom of Nectria cinnabarina is the die-back of branches. Once the branches die the fungus appears; as seen in this image. 

It is best to cut off infected branches down to healthy wood in dry weather to prevent the fungus from spreading. Destroy the infected wood by burning it to prevent the fungus re-attacking the surrounding woody perennials as there is no cure or specific fungicide for this disease.  

Image taken by myself.