Spoiler tactics at the opposition's convention / conference - an interesting US / UK comparison

Here's a very interesting article on significant Republican operations during the Democratic convention in Denver.  I'm sure that the boot shall be firmly on the other foot come the GOP's turn, so there's no party political point to be made here - there is, however, an interesting parallel to be drawn with politics in the UK.  We think of politics here as a professional and bloodthirsty business, but nothing like this - at least on this scale - really happens here.