What is a substitute for the blood sausage?

Hi Jamie. As QueenSashy says, there's no good substitute for it although if I have to think about something, I'll say that some mild chorizo or even a lamb sausage will be great with this. The trick is that it should be made in a way that it will allow you making a paste out of it after removing the casing. I hope it helps!

There is no good substitute for blood sausage, because as its name implies, it is made with pig's blood, which imparts a characteristic flavor to it. However, I am pretty sure that this tapas will taste great with a good quality chorizo, or merguez. It is not going to be the same, but it will be good.