I created a data importer for the UK Companies House free dataset. This currently includes 3.2 million uk registered companies along with detailed financial records. I geo-located the companies, cleaned the address data and classified the companies into high level industry categories.
I'm now able to answer questions, like for example who are richest (or poorest) companies in a given geographical region and/or business sector or any number of interesting statistical questions about the nature of business in the UK. It's surprising that such an incredible data source is available for free, but it is !
Very interesting information, but I haven't managed to think of an actual use for it ! There are no contact details other than the companies registered address.
Anyway, I used that data to create the interactive chart shown below. I can't publish the actual chart right now as it contains commerically sensitive information. Sign up for my newsletter and I'll keep you informed :)