Can Uk citizen resident in EU work 3 weeks a year in UK have NI number

[DanielTo]

Hello,

My son has holds both British and Italian passports. He lives in Italy and returns to the UK to work with me 3-4 weeks during his holidays as part of his secondary schooling (he is studying IT/ programming). For the rest of the year he schools and is resident in Italy.

I would like him to start building up a public pension. As I pay him for this work:

1. Can I pay him into a UK bank account in his name?
2. Can he open a National Insurance Number?
3. Can he pay NICs?
4. What would be the best way to pay him? This is his only paid work so does he declare in UK or Italy?

Thank you