Is an unpaid internship secondary employment?

[randomite]

Hello,

I'm currently employed here on a Tier 2 General visa. Recently, I found a startup doing some interesting work that I'd dearly love to contribute to. I'm not looking to get paid by that startup, I just want to get some experience working with them.

However, due to NDA clauses and such, they don't offer informal volunteer positions - instead, they're asking if I can sign on as an unpaid intern. This is where I get stumped, as I can't find the answer in the Tier 2 policy guidance. If I sign on as an intern, does this mean that this will be considered secondary employment? Does it matter that it's unpaid?

[iworker]

i think as long as u are not getting paid and your primary job is not affected, u should be fine.
IMHO