Patriot games.

Patriot Games is a thriller novel, written by Tom Clancy and published in July 1987. Without Remorse, released six years later, is an indirect prequel, and it is chronologically the first book featuring Jack Ryan, the main character in most of Clancy's novels. The novel focuses on Ryan being the target of Irish terrorist group Ulster Liberation Army for thwarting their kidnapping attempt on the Prince and Princess of Wales in London.