One word: Why? 
Why did Janet Wilson give that interview to the Spinoff? 
This is not good strategy.
Janet Wilson was Judith Collins’ press secretary during the last election campaign. She was asked by the Spinoff news website for an interview and declined. But after Collins had a go at Siouxsie Wiles last week, out of the blue on Saturday, Janet text the Spinoff and said yes.
In the interview… she slates Collins. 
She says Collins "prizes loyalty above all else. But then her ugly stepsister, paranoia, steps in, and she has these almost paranoid storms."
And then this assessment of the party's problem: "The enemy is within, it’s not outside. Act is merely capitalising on what’s happening within the Nats at the moment and their complete lack of discipline on all levels."
None of it is particularly enlightening. I didn’t learn anything I didn’t already know. I already knew – and I’d imagine you did too, that Collins is erratic in her strategy and either doesn’t’ take advice or takes bad advice. So, there’s very little value in the content. The interview’s only real worth is that it is shocking how badly this party is disintegrating.
But, it’s rich of Janet Wilson to accuse to the Nats of a lack of discipline when she gives an interview like this.
I can only hazard a guess at why Janet did this, and my guess is that she decided she needed to distance herself from Collins reputationally, that she needed to put it out there that none of Collins’ bad calls were because of her advice. I'm not sure this will work. This is not reputation enhancing. This is a bad call.
It never looks good when a former staffer turns on the boss. Look at Dominic Cummings turning on Boris Johnson in a series of repeat public attacks. Who came out of that worse? Cummings did. 
In this case, the real victim is the National Party. Because the more people associated with that party turn on each other like this, the less trust people have in the entire lot of them.