Population

Can you tell me which is correct:
'the UK's population is' or 'the UK's population are'?

Hi
Though the word Population is often used as an uncountable noun as Beth says, it can also be considered as a countable group/collective noun (we see 'population' as a whole unit, not as many individuals). When it is considered as a group noun, we use the singular form of the verb, i.e.....IS.
So, as you both said....The UK's population IS....is correct.

I think it can depend on what follows, e.g.

The population is wiser than you think. (You are thinking if the population as a whole)

The population are idiots. (You are thinking of the individual members of the population)

There is no hard and fast rule about whether collective nouns take a singular or plural verb.