There are several free on-line directories that are useful both for finding services you require and for researching the local competition.

Near.co.uk is a good example, and one of the simplest and quickest to use. It provides a straightforward list of businesses by type and town. For example:
Wedding services near Widnes
Chain saws near Chepstow
Car auctions near Carshalton
The data for Near’s listings comes from Thomson local directories, so it’s generally up to date. What’s good about Near is that it presents the information in a simple and clear way.
Yell is the Yellow Pages equivalent. The interface is a bit more cluttered but you can plot results on a map. On some of the examples we tried it seemed to have fewer entries than Thomson-based Near. But it is a more a intelligent system than Near, and will suggest a range of different sorts of supplier that might, for example, offer chain saws for example, rather than giving up after finding only one result.
But probably the best of the simple listing sites is - rather surprisingly, BT’s online phone book. This now has an excellent business look-up function. It’s fast, returns numerous results, and will suggest other relevant categories. Here’s the chain-saws in Chepstow query for example.
This service is free for “personal use”, and you can increase the number of results per page up to 50 in the preferences menu. So you could obtain the details of lots of businesses.
Thomson Local, the source of Near’s data, is another site well suited for compiling big lists. Compared to Near you need to think a bit more when using it. For example it returned no results for a simple query about car auctions in Carshalton - because strictly speaking there aren’t any. But if you manually widen your area of search to Surrey or the South East it starts finding them. So it’s a bit literal in how it handle queries. But it has vast amounts of data and is good for scanning large areas of the country.
There are limitations on using any of these sites for compiling big lists. Partly these are practical. Thomson Local for instance limits the results returned to 200 in any one search, so if you are looking for a very popular category like pubs in the South East it will miss a lot.
There may also be restrictions in the terms of use that seek to prohibit you from using the data from the web site “for any kind of direct marketing, telemarketing or electronic marketing”. Whether or not these are enforceable in law is a moot point, but if you use the site heavily you may find it stops working.
What’s going on here is that many of these firms have other paid-for products that they would rather sell you for compiing big lists. These can be more convenient and indeed cost effective, by for example allowing you to sort on more criteria so that less of your mailing effort is wasted.
Returning to what’s available for free, UpMyStreet is a more elaborate site going well beyond a directory, but it’s worth investigating as it offers others sorts of free information that may be useful for your business. You can simply use its Find My Nearest feature - here’s the results it returns for car auctions near Carshalton, which are displayed by default on a map.
But it can also tell you much more about a neighbourhood in response to a post code or town name. This includes a brief free Acorn profile - Acorn is a marketing system that attempts to describe the type of people you can expect to find in the area, including their likely income level, age, the sort of homes they live in and some of their consumer interests. Here’s what it thinks of the residents of Chepstow.
Elsewhere on the site you can find out about local property prices and crime statistics. Obviously these features are mainly aimed at home buyers. But they are also of interest when researching likely areas for customers or premises.