Well, let me just make a disclaimer; I adore Andy Serkis, think he was an excellent Smeagol, and liked him in the other movies I've seen him in too.
But why, oh why, does the Witch King have to have a West London accent?
It's Serkis' real accent, and works for Shagrat, but it's just silly from the WiKi. Why Jackson didn't tell him to change it I cannot fathom - he could have.
The accent makes all the WiKi's lines sound incredibly cheesy to me.