His outspoken opinions on cats have infuriated thousands of owners, but economist Gareth Morgan says cats are serial killers and need to be controlled or culled.
He's had cameras back in people's gardens filming prowling cats and today released the results.
"My request of every cat owner in New Zealand is to make this cat your last," he says.
Mr Morgan wants all cats micro-chipped and registered.
"They're defecating, and that's the first thing, so that's a toxoplasmosis issue, but the thing I'm far more concerned about is the wildlife."
The economist-come-environmentalist has been filming cats again – last time in the capital, now in Auckland.
Cameras were moved around 20 Auckland properties over 388 days and nights, revealing cats prowling in someone else's garden 694 times, or about twice a day.
Mr Morgan says that's more than 300 million cat invasions every year in Auckland alone, mainly by domestic cats, and that wandering cats should be caged.
"In the case of an un-owned cat they should be destroyed just like a dog would be," he says.
Mr Morgan has been a cat owner.
"When you have kids you have cats and then the kids go and then you think, 'What have you got these bloody cats for?'"
Mr Morgan's cat did live a long a life. Under his plans, responsible cat owners would make sure theirs did too.