Patriot Games (1992)

Former CIA analyst, Jack Ryan, is in England with his family on vacation when he suddenly witnesses an explosion outside Buckingham Palace. It is revealed that some people are trying to abduct a member of the Royal Family, but Jack intervenes, killing one of them and capturing the other and stops the plan in its tracks. Afterward, he learns that they're Irish revolutionaries, and the two men are brothers. During his court hearing, the one that's still alive vows to get back at Jack but is sentenced, and that seems to be the end of it. However, while the man is being transported, he is broken out. Jack learns of this but doesn't think there's anything to worry about, but when he is at the Naval Academy, someone tries to kill him. He learns that they are also going after his family, and so he rushes to find them: safe but having also been the victims of a failed assassination. That's when Jack decides to rejoin the CIA, and they try to find the man before he makes another attempt.