Government

It is always regarded as an external stakeholder despite passing laws that affect businesses in fundamental ways and, also, setting tax rates.

Similarly, shareholders are usually regarded as connected, but at annual general meetings they are very much internal in terms of their control of the company.

I know for BT you have to be able to identify external/connected/internal, but in practice the categorisation often makes little difference. What is more important is their power and level of interest.