I have trouble with this huge plothole in Sherlock Holmes.
In the movie Holmes enlightens Lord Coward that he knows about the machine in the sewer to kill the lion (parlament).
After that Lord Coward does not seem to care since the machine is not really protected (around 5 people). The same goes for Blackwood assuming Lord Coward told Blackwood about Holmes knowledge.
If this event was so important to Lord Coward(as far as I know he believed in the magic) why would he not make 100% sure to protect the machine (I would put around 30 people in the sewer, even if Holmes would still find a way around that I had at least tried).
Again same goes for Blackwood except he doesn't believe in magic. His goal was to dominate with fear and not the mechanism of the machine itself. The mechanism was only important for the mysterious professor.
Please mark spoilers of the second movie if those reveal/solve this problem.