[davb]

Or anything involving legal system/jurisdiction or company registration (both of which are differ between countries within the UK).

The UK and the Netherlands are both (according to ISO 3166-2 [0]) countries which contain other countries.

[0] https://en.wikipedia.org/wiki/ISO_3166-2

[crote]

In the case of The Netherlands, this is plain wrong.

The Kingdom of the Netherlands contains four countries, being The Netherlands, Aruba, Curaçao, and Sint Maarten. According to ISO 3166-2, there exists a country "The Netherlands" which contains the other three. Close, but not correct.