Now ain't that the truth Ian.
Rhrosty.

I'm not sure it has anything to do with scripts, Mr Nance.

Anyone who is in a position that might involve interaction with the media undergoes this ritual called "media training". It is a methodology - quite a standard one, in fact - that teaches you how to manage these interactions.

It involves learning two core capabilities. The first is to ensure that you have rehearsed the exact message that you wish to relay, beforehand. Then, during the interview itself, to convert each of the questions posed to you, into the basis of a response that allows you to convey that message. Armed with these two skills, you can turn any interview into a simple platform for your company's, or your Party's, key message.

This explains why no politician will ever answer the question posed, but will riff into his/her preferred topic, without even the slightest blush of shame.

Those who have not internalized these skills will inevitably fall apart in front of the camera or microphone. The downside is, of course, that every single one of these interviews (with the exception of the rare, unprepared example - step forward Ricky Muir) is entirely empty of useful information.