The Queen

The final film shows the Queen (played by Diana Quick) confronting one last personal and constitutional challenge: Prince Charles' desire to marry Camilla Parker Bowles.

First, the Queen had to endure watching Diana tell 200 million viewers around the world in her 1995 Panorama interview that there were 'three of us in the marriage.' It was not surprising that the subject of Camilla was, according to one former courtier, 'off limits' in the 90s.

Yet ten years later, the Queen welcomed Camilla Parker Bowles into her family with at least half-open arms. How did this happen? Why did the Queen go against all her most ingrained prejudices and heartfelt beliefs? How did she finally leave behind preconceptions that went back to the abdication crisis of 1936, in order to accept her son's middle-aged mistress as her new daughter-in-law?

Not least as public opinion had been telling her that the very popularity and survival of the monarchy was at stake. At first the Queen would not even hear Camilla's name mentioned in her presence. And yet, somehow, she came round to the idea.

This programme examines how the Queen - the ultimate survivor and pragmatist - ushered in the last chapters of her reign by eventually bowing to the inevitable, accepting Camilla, and going some way towards repairing her relationship with Prince Charles.

As the Queen's former press secretary Ron Allison puts it: 'You could look at the 50 years between 1955 when Princess Margaret did not marry Group Captain Peter Townsend, and 2005 when the Prince of Wales did marry Camilla Parker Bowles. And that is just about as remarkable a change as you could imagine.'