By Michael Morrah
Questions about the Prime Minister's personal security have been raised after his security staff failed to spot the recording device left on his and John Banks’ table.
A private security consultant says in his line of work such an oversight would be considered an indefensible failure, but John Key says he has only himself to blame.
Mr Key's bodyguards are always part of his entourage and part of their job can involve venue security and searches.
“Because [the recording device] was enclosed in something, no one knew exactly what it was… the risk is high,” says Paragon Security Advisor Wayne Kiely.
Mr Kiely says in his line of work such an oversight is worse than unacceptable.
“I think the person responsible would be sacked. It's intolerable that that sort of lapse in the private sector could occur.”
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The police employ the diplomatic protection squad to look after the Prime Minister, but Mr Key, who has complained to police about the recording, is taking the heat off them.
“I think I have to take personal responsibility for that . At the time I was focused very heavily on looking at John banks and the conversation that was going on. There was a lot of media around us.”
Freelance cameraman Brad Ambrose put the black bag, which contained his microphone, on the table to get audio while Mr Key and Mr Banks were taking questions.
Mr Ambrose says as he was ushered outside, it was left there by mistake.
“It's just been blown into something huge . And it was honestly just a small, minor mistake that's just kept going and going and going,” he says.
Mr Key has called the recording "News of the World tactics".
But the lawyer representing that paper's most famous victims, Milly Dowler's family, calls the comparison "a cheap shot" to deflect attention.
Mark Lewis says a better comparison is with Britain's Prime Minister Gordon Brown own recording nightmare, when he was caught on a forgotten-about microphone calling a woman a “bigot” .
• Click here for the full interview with Mr Lewis
Mr Kiely says there are ways to covertly record a conversation - he even secretly recorded our interview.
This was a legal move by the security expert because one party was aware of the recording.
But in the case of the teacup tapes, neither party gave consent.