When it comes to SEO industries one of the leading countries without a doubt is the UK. There are many high level agencies in the UK and the developments are going very rapidly there.
Whether or not the UK industry is much better or worse than other countries is hard to say, not just because it is difficult to look at specific agencies, but also because the environment can be different in each country.
Still, you can try and look to the UK by looking at the numbers. Numbers that show that the UK SEO industry is not just focussing on SEO anymore, but also heavily involved in Social Media and Web Analytics for example. Or that most agencies have a blog. And that the good old fashioned “SEO Agency” seems to be replaced, as a name that is, by “Digital Marketing Agency”. This infographic sums it up.