Why do Irish & British sausages have soft casings? Growing up in Ireland has given me a certain expectation about how a sausage should taste. Travelling the world however, has taught me not only that most Irish and British sausages tend to have softer casings than elsewhere, but that this is actually the exception, rather the norm. Indeed it seems that in most places, tough casings are actually preferred, and that my personal preference is actually the aberration. 

But enough preamble; what is the reason that British and Irish sausages tend to have softer casings?
There are many potential variables here, particularly if the sausages are made with natural casings.  More likely it has to do with the actual casing source.  Casings from beef are different consistency from casings from hogs and from lambs.  I have found that hog casings are the softest that I have used, but I am in the US, not in Britain or Ireland.  I have also found that casings from different suppliers are different.  The ones I can buy locally in small quantities tend to be much tougher than the ones that I purchase online from a commercial provider.

I am guessing you have a situation where the sausage makers in Britain and Ireland have access to very high quality casings that are softer.

Some of this may be due to the diet of or the breed of animals that provide the casings.