'I'm a US Senator...'
In the movie Shooter that line is also mentioned just before the corrupt Senator is executed. In that movie Mark Wahlburg replies with "Exactly" before blasting the bad Senator. In this movie Winstone replies with something like "is that what you call it?". I preferred Shooter's one liner.
If I were in that situation my line would have been: "I am a US Senator!" - "Not any more MFer!" kaboom!