Webmail "Report as Spam" - what does it do?

I sometimes check my webmail.spamcop.net account, and recently more and 
more spam makes it into it. There is an option "Report as Spam" on top - 
what does it do? It seems not to go to the normal spamcop reporting (as 
from the Held Email queue when selecting Queue for Reporting).

Nothing about it in Help either.