The freelance tag has been added to the database. I know that questions and answers in the archive on this topic have been the occasion for (let us say) a 'spirited' exchange of views. And yes, some answers I have provided are now obsolete (and hence inaccurate) by changes in policy. I'll have to fix them.
I suppose in the face of Brexit and whatever, that we'll see more of these questions in the future. I also suppose that with the UK's consideration of their new 'preferred' tier regime, we'll see more. But these are mere suppositions.
If you are reviewing the archives and spot a relevant question, please add the 'freelance' tag. If you dupify or hammer an incoming question, please properly tag up the canonical. It may be helpful to add and define the same tag on Expats also.