Award-winning novelist Hilary Mantel has defended her comments on the Duchess of Cambridge after saying she was becoming "a shop-window mannequin" who was "designed to breed". The author insisted she had nothing to apologise for.

The double Booker Prize winner hit the headlines last month when she referred to the duchess during a lecture at the British Museum as having no personality and appearing to have been "glossed-varnished" with a perfect smile.

In an interview on BBC Radio 3's Night Waves programme on Thursday night, she said her words had been taken out of context and had no regrets about her comments.

"My lecture and the subsequent essay was actually supportive of the royal family and when I used those words about the Duchess of Cambridge, I was describing the perception of her which has been set up in the tabloid press," she told presenter Anne McElvoy.

"My speech ended with a plea to the press and to the media in general. I said 'back off and don't be brutes. Don't do to this young woman what you did to Diana'.

"My whole theme was the way we maltreat royal persons, making them one superhuman and yet less than human."

Mantel, whose latest novels are set in the Tudor court, said she believed she had been set up.

She told the radio programme: "I don't believe for one moment that there was any lack of clarity, after all, I have been practising my trade for a number of years now.

"It was a matter of taking the words completely out of context – twisting the context – and setting me up as a hate figure. I have absolutely no regrets. What I said was crystal clear."

During the controversial lecture, organised by London Review of Books a month after her latest novel Bring up the Bodies won the Costa prize, Mantel suggested that "painfully thin" Kate was selected for her role of princess because she posed no risk of showing any character.

But she said on Radio 3: "I do think that the Duchess of Cambridge is an intelligent young woman who, if she cares to read my essay, will see that I meant nothing but good to her."

• This article was amended on 8 March 2013. The introduction originally referred to Mantel's criticism of the Duchess of Cambridge. In fact, she was criticising the media's treatment of the duchess. The introduction has been corrected.