Why does jaggers call wemmick the "most cunning imposter in all of london? "

Jaggers calls Wemmick the most cunning imposter in all of London because Jaggers disagrees with what Pip said that Wemmick is a kind-hearted person. Because the Wemmick that Jaggers knew is different from what Pip described him to be. The Wemmick that Jaggers knew is different. The Wemmick that he knew can often be such a calculating individual in his business dealings. That is why Jaggers jokingly referred to him as the most cunning imposter in all of London. 

The first sene: alice was performing a magic trick with a wand and a small spell book that her grandfather had given her. while she was practicing she saw matt who was one of the other contestants, while she was practicing matt bumped in to her and made her say the spell wrong. all of a sudden a swoosh of sparkling purple wind picked them up and put them back on the floor. when they looked at each other alice saw herself and that’s when she realized that they had switched bodies.