It's made in Burton near where I work. The yeast being a by-product from the breweries in Burton.
Slightly salty?? very if like me you don't put salt on your food.
It isn't that popular in Britain really, when I was a manager of a medium (12,000 sq ft) sized supermarket we sold maybe 1-2 cases of 24 jars a week.
I think the stuff is vile!!!
vegemite as sold in Aus, is similar.
I forgot to mention that the factory absolutely STINKS.