I saw it last week, and so far, it's my favourite film of the year.
The single swear word used is when Tony and Cherie go for an audience with the Queen on the day after Labour win the 1997 election.
After they meet with her, they're walking down the stairs to the main hall in Buckingham Palace and Cherie says something along the lines of, "She keeps us waiting for ages, and all you get is five ****ing minutes".
It is a truly excellent film, and if Dame Helen Mirren isn't nominated for an Oscar, I shall be tutting loudly and complaining to acquaintences.