The Robin Hood Tax

This is taken from the excellent six-part BBC series "State of Play," with Bill Nighy as the politician. Here is the plot summary from IMDB:

"A thriller set in London, in which a politician's life becomes increasingly complex as his research assistant is found dead on the London Underground and, in a seemingly unrelated incident, a teenage drug dealer is shot dead."

"State of Play" was remade by Kevin MacDonald into a 2009 feature film with Russell Crowe as the reporter and Ben Affleck as the politician.