However, if you mean readily available in the UK or, dare I say it, from the supermarket (nothing super/superior about them in my opinion) then Booths' Cumberland/Lincolnshire/Toulouse all take a bit of beating. Our local slaugherhouse is also a farm shop and they do a very good range, frequently seasonally based (pork and chestnut at Christmas for example).
I look for pork-based sausages, beef is OK. What few real butcher shops that we have left over here usually have a variety of seasonings and smokings.
Gawd only knows what`s in the tubular things in the big box grocery stores.
So: pork with onion, black pepper and just enough apple wood smoke that I can smell it.
Of the British sausages I like Venison. The Saffie Boerewurst is delicious. Then the Swedish or Norwegian Wiener korv.
Blood sausages type Boudin Noir, the French, German or Czech version does not matter.
I almost prefer sausages of all sorts and types before pure meat!
All the more reason to make a New Year's resolution, starting today: Make a list of all those sausage types.
Never buy the same thing twice. Culinary adventure between now and the end of the year.
I lied. I have a stash of venison Farmer's sausages in my freezer. Traded for some bison.
Half of one of those with sides is a big supper for me.
The butcher shop does mostly game cutting (Chilako Meats) with a far flung reputation for excellence.
#1 : the homemade sausages of a good friend of mine, made from his own free ranging cattles near darwin. Sadly he passed away in 2007 so I'll never be able to taste this treat again.....
#2: thuringian sausages (more than a decade since I had my last)
#3: the camel-curry and water buffalo-chillie sausages from the butcher in Humpty Doo (top end/OZ)- which I hadn't in years, either....
finding something what deserves the description "" sausage"" here in Korea IS a challenge: even my friends cats refused to eat the things sold as hot dogs here (so you may guess what's inside.....)