Foreign Professional Referee for Naturalization

[kaboo]

Hi, guys.
I have a question re referees for my Naturalization application. The form and guide say that you can normally use a person with a professional standing of any nationality and has known you for 3 years. Can it be someone living abroad? Does it only apply to people applying from outside the UK? Or can I include someone like that on my application if I'm applying from the UK as well? Do they have to provide any extra info about themselves? I.e. certified copy of their passport page showing their photo and signature or a cover letter etc?

[milan69]

Referees just have to write their details in the form and state how they know you.

[fwd079]

Can it be someone living abroad? Does it only apply to people applying from outside the UK?

Seniors can correct me, but in my view the address of referee should be in UK.