11:58AM BST 12 Aug 2011
"We had gone through all the questions and subject matter beforehand and filmed all the walking in the park footage before we sat down," he told the Sydney Daily Telegraph.
"She did walk out when she was ambushed – no, it was entrapment – but after cooling down she said to me, '**** them, let's do this', and she did, but it was a banal interview and her demeanour reflected that."
The Nine Network has refused to pull advertisements for the interview, which is scheduled to go to air on Sunday night.
"He would be naive to think that we wouldn't use the most dramatic feature of the interview to promote the story, he's a professional media manager," Mr Thomson told the network's website, ninemsn.com.au.
On his blog, Mr Usher wrote that he originally thought he was getting on well with the Duchess, before "it went a bit south."
He went on to describe her as icier than "the wilds of the Arctic," saying the interview was testing and tense but also revealing.
60 Minutes, which is proud of its hard-hitting and often sensational style of journalism, is known for annoying celebrities. In 2005, Tom Cruise became upset and demanded that interviewer Peter Overton "put your manners back in" after he was questioned about Scientology and his marriage to Nicole Kidman.