LONDON – Britain’s Queen Camilla fought off an indecent attack when she was a teenager by taking off her shoe and bashing the assailant in the groin, according to a new book on the royal family.

Camilla was on a train to London’s Paddington Station in the mid-1960s when the man next to her reached out and attempted to touch her, according to an excerpt from “Power and the Palace” by Valentine Low, a former royal correspondent for the Times of London. She told former Prime Minister Boris Johnson about the attack when he was mayor of London.

“Camilla said, ‘I did what my mother told me, I took my shoe off and whacked him in the nuts with the heel,’’’ Low told the BBC. “When she got to Paddington, this in a way is the crucial bit of the story, she found a man in uniform and told him what had happened and the man was arrested. … She did the responsible thing.’’

The story drew widespread coverage in the British media on Monday, with headlines ranging from the Daily Telegraph’s basic “Queen fought off sex attacker” to the Sun’s tabloid-style “Camilla whacked groper in goolies.” Whatever the approach, the tale is sure to add to Camilla’s reputation as a no-nonsense woman who has brought a bit of grit to the royal family.

The story was related to Low by one of Johnson’s former aides, who believed the incident was the reason for Camilla’s outspoken support for charities that work with victims of domestic violence. She has been reluctant to speak about it because her experience, while upsetting, was less serious than the attacks suffered by other women and girls, Low said.

“She didn’t want to draw attention to her at the expense of their experiences,” he said.

Buckingham Palace declined to comment on the report.

“Power and the Palace” will be published later this month. But the book, which details the relationship between the monarchy and Britain’s political leaders, has already attracted attention with excerpts published in the Times of London that suggest the late Queen Elizabeth II opposed the U.K.’s decision to leave the European Union.