I just thought it was a triumph of writing .. and acting, and imagery.
After his escape; Tommy fled to the high moors, leaps off the bike; such a superb physical specimen. He stretches out his arms and embraces his freedom and the open horizon as if he's king of the world.
And at the end; Catherine describes his lovely son Ryan ending with "He's a prince.
Tommy and Ryan are sides of the same coin; both born into terrible circumstances; one damned but the other saved . They were forced apart, then drawn back to each other like magnets, and finally father and son understand something of each other, and more of themselves.
Just superb.
And finally... SW needs no more words. Catherine's no-scarf bare neck and bright fitted jumper say it all.