Sorry if this is a FAQ - I did look …
I’m a freeware developer and want a comprehensive, accurate and free list of UK places with their OS grid references. I don’t want OS map images. I’ve googled a lot but found nothing that is suitably comprehensive, accurate or, er, free.
Any advice, suggestions?
Suggest you use geonames.org. You may need to convert from lat/long to OSGB, there are plenty of Perl modules and the like to help you do that.
But geonames is a very stupid dataset, it’s derived from US sources which makes it prioritize names that aren’t relevant at all to the local country.
If you want very accurate and very comprehensive buy it from OS.