UK Child Visa requirement prior to section 3(5) citizenship application

A divorced parent, British citizen by descent, with a 12 year non-British child, wishes to move to the UK, with the child, next year. The objective is to attain British citizenship for the child, via section 3(5), after 3 years residence. The parent has the consent of the ex-partner.

Does the child need a visa? If so, which one, and can it be acquired before parent and child move to the UK?

Yes, the child does need a visa to move to the UK if the child is a non-British citizen (all non-British citizens, whether adults or children, need a visa or leave to remain to reside in the UK legally).

Assuming that the parent can prove sole responsibility, they can apply for the usual dependent visa, with the British parent needing to meet the usual requirements for one dependent (annual income of £18,600 per annum or savings of £62,500, etc).

If the British parent has sole responsibility, etc., then child may require adequate maintenance.