Imagine you are sat in your garden one summer evening enjoying a Pimms and lemonade when over the trees and into your garden looms an interstellar spaceship and from it's bowels, a light shines from which a strange form is gradually lowered down and you find yourself face to face with an alien.
'I am an ambassador for Clor the Mighty of the 8th Grand Galactic Intra Demarcate' says the alien 'who would make it known to the natives of this world, that they are to be put on trial at the Sovereign Earthly Nations Court of Justice for crimes against the Universe so take me to your leader'.
'Blimey' you may say and wish that there was some sort of protocol for when aliens turn up unexpected and demand to be taken to our leader.
The Philosophical Transactions of the Royal Society have been pondering the same thing and they think that World governments should be preparing a co-ordinated action plan in case alien crafts land on Earth.
They think the responsibility of acting on behalf of Earth should fall to the United Nations and a branch set up for 'supra-Earth affairs' to establish protocol structures.
The discussion is still on-going so no decision yet of who exactly the leader is that we should be directing them to but if they are holding an anal probe then there are a few World leaders you could direct them to as long as they promise not to bring them back afterwards.