Morcón
From Cookipedia
Morcón is a peculiarly-shaped (a little like a badly wrapped parcel) dry cured Spanish sausage and is similar to chorizo. It is made from the shin and/or shoulder of a pig and it is cured in an intestine called a morcón.
It originates from Andalucía and Extremadura and always contains paprika. Those from Extremadura are generally made from Ibérico de Bellota pigs.
The only UK supplier I have found is Bellota.