The story is satisfyingly complex and the characters have been developed beyond the two-dimensional ciphers that usually serve in this kind of movie.

In both novel and film, Ryan is the moral centre, but the film jettisons the book's range of supporting characters whose differing values help define his position.

This is the third movie with Jack as its hero, so he is a known quantity -- a humanist spook with an overdeveloped moral sense -- but Ford, playing the part for the second time, knows how to keep his earnestness fresh.

Harrison Ford is on commanding form for his second outing as CIA troubleshooter Jack Ryan and director Phillip Noyce makes a much better job of this than he did of The Saint.