Course of justice seems to have a different meaning in the United Kingdom. Case in point. "Liberal Democrat cabinet minister Chris Huhne [...] plead guilty to perverting the course of justice by asking his wife to take his penalty points on her driving licence 10 years ago." Speeding points! Ten years ago! Her trial is still coming.
Not only did this cause him to resign, but he "faces very heavy legal fees and a possible lengthy jail sentence." And, "he also expects to be expelled from the Liberal Democrats for perverting the course of justice." [Nick Clegg 'shocked and saddened' by Chris Huhne's guilty plea, and see Chris Huhne facing jail sentence after admitting perverting course of justice].
And the relation between the police and the politicians often seem at odds with each treating the other with disdain. Class tensions? A recent case, October 2012, in point. A "row developed after police refused to open the [10 Downing, Brits' White House] main gates to allow him [Andrew Mitchell chief whip] to take his bicycle through, instead forcing him to use the side gate." The police alleged that he called one of them a 'pleb' and 'moron.' He resigned. [Andrew Mitchell resigns following allegations he called police 'plebs'].
But take notice that his resignation wasn't the end. British police arrest second man in plebs inquiry - fabricating evidence. It appears that the resignation was unnecessary.