The famously feisty Princess Anne very nearly punched an armed man who tried to kidnap her in 1974, only stopping herself out of fear she might be shot, say newly released files from the era.

Then aged 24, the daughter of Queen Elizabeth repeatedly refused to get out of her car when it was ambushed by Ian Ball, a small-time burglar with mental health problems, on March 21, 1974. "I nearly lost my temper with him, but I knew that if I did, I should hit him and he would shoot me," Anne recounted to officials, in testimony in files released to the National Archives.

Robert Armstrong, the private secretary to then prime minister Harold Wilson, who wrote up the account, and his boss were clearly impressed. "A very good story. Pity the Palace can't let it come out. Perhaps it will in court," Mr Wilson wrote in green ink at the top of the page.