Judith Collins says her former boss Sir John Key "may have" feared she'd try and roll him - but she "can't imagine why".
The veteran National MP has just published a book, Pull No Punches: Memoir of a Political Survivor, in which she takes aim at Sir John, who infamously had her resign during the 2014 election campaign.
Collins stood down while an investigation was carried out into alleged conflicts of interest, and she was stripped of the right to use the title 'Honourable'. She was later reinstated to her ministerial roles after being cleared of any wrongdoing.
That was just one of a number of conflicts between the pair, and Collins says despite working together for many years, they were never friends.
"John always used to say to me and others he had colleagues - not necessarily friends," she told The AM Show on Monday.
"We always got on okay, but we were never so close - we never socialised together."
Asked by AM Show host Duncan Garner why, Collins said she didn't know.
"I'm not one of the boys, am I? Never have been."
Leadership rumours have circled around Collins ever since Sir John unexpectedly stepped down in 2016. She put her name in the hat to replace him, but pulled out when it became clear Sir Bill English had the numbers. She ran again in 2018, but was defeated for both the leader and deputy roles by Simon Bridges and Paula Bennett.
Since then Collins has had to regularly had to fend off rumours she had plans to topple Bridges, who struggled to get voters' approval throughout his leadership.
But she thinks Sir John, despite his enduring popularity in the polls, might have been wary of her ambitions from an early stage.
"He may have been - I can't imagine why," she laughed. "I think he may have worried about me, but unnecessarily actually because I was quite happy doing what I was doing. I didn't quite see that, but in hindsight - when I wrote the book - things became much clearer."
Collins said she has no plans to challenge current leader Todd Muller. National has had a bump in the polls since Muller took over from Bridges, but it's hard to tell at this stage whether that's voters preferring Muller to Bridges, or just a reversion to the mean after Labour's stratospheric polling in the wake of stamping out COVID-19.
"It's not going to happen. It's not going to happen because we're going to do really well and I'm backing the leadership."
Reviewers have noted the book, despite its title, does appear to pull some punches - with little mention, let alone criticism, of most other National Party figures.
"I didn't want to hurt anybody's careers unnecessarily. I just think it's important to have a bit of space between things and understand everyone's got their own views on life. There's the odd punch pulled."
Whether it changes the public's perception of Collins as tough - like her 'Crusher' nickname would suggest - remains to be seen. Collins said she never liked that nickname, endowed on her in 2009 after she pushed through legislation allowing police to literally crush cars belonging to boy racers who keep breaking the law.
A cartoon published in the Listener in February 2009, just two months after she became Police Minister, showed Collins driving a steamroller over a car, with the 'Crusher' nickname on the front of the vehicle.
"That is a caricature. It came from cars, and by the way I never stood there on cars or do anything like that. I hated that whole image."
It was actually her successor as Police Minister, Anne Tolley, who crushed the first car and posed for a photograph standing on top of it in 2012.