Mouth of Sauron

[Essex]

for me the MoS looked very creepy. I love the way his head moves as the hobbits wimper- as if he has tunnel vision, or maybe no vision and relying on an acute sense of hearing.

oh dear here we go again -

he is an ambassador

Book MoS was an ambassador there to parly. Movie MoS was no ambassador at all, and did not claim parly either. He was there to taunt them before his troops ripped them apart. (and to be honest that was what the Book MoS was there for - Sauron knew our Heroes would not surrender - remember he thought they had the Ring - it was just a trap to draw them close so he could spring his trap anyway)

Movie Aragorn chopped his head off to shut him up. He was putting major doubt into the minds of the Men of the West and Co. and had to stop it. As he said after he did the deed - that he would not believe what the MoS was saying, so off with his head!