The more he and his great leading actress came to know of the Queen, the more royalist they seem to have become. The result is that they have created a royalist film; it is practically a hagiography. The film The Queen will work public relations wonders for the House of Windsor. This is all the more astonishing because neither Frears nor Helen Mirren is the kind of person you would expect to have a single good word to say about the Queen. Luvvies tend not to be courtiers.

Mirren was brought up as a working-class republican and, as she said recently at the Venice film festival, she was determined not to appear as a “grovelling knee-jerk royalist”. “But,” she went on, “I must say I slowly fell in love with her. It started off with, ‘Oh what the hell is this about?’ But as I researched her I fell in love and I never thought that would happen.

“My parents were very anti-monarchy and anti-class system, but you’ve got to separate your political views, call it your chip on the shoulder, and just look at the person . . . Having played an essence of the Queen, I’ve lost that chip on my shoulder.” This is from a woman who once said she thought the Queen withholding, cold and rather greedy, and that she would like to see the monarchy abolished.

Frears, too, seems to have surprised himself with his own sympathetic portrayal of the monarch. “The Queen is someone who has been in my life far longer than anyone else — longer than my children, my wife or my brothers — so of course I’ve got complicated, unconscious feelings. Oh God, it’s deep stuff.” Indeed. But what about his mother? Perhaps that’s rather deep, too, perhaps “a Mummy thing” as Frears’s Alastair Campbell suggests to the film’s Tony Blair; the unconscious feelings that surround the throne are very deep. Even those who would like to ignore them seem to find they can’t.

The film deals with the famous week that probably came close to destroying the royal family. After Diana’s death, when the royal family stayed in silent seclusion at Balmoral without making a public statement, the people turned on them with a violence we have almost forgotten. So it seemed, to judge from the news, but I remember thinking at the time that the tabloids actively encouraged people to denounce the royal family to the cameras and call the Queen’s behaviour “ disgusting” and “disgraceful”.

Media-led or not, this frenzy was catching: an opinion poll during that week found that one in four people wanted to get rid of the Queen. It was a sanctimonious time; one could almost hear the tumbrils rolling. The Queen was expected, in the spirit of Diana, to go touchy-feely and come out to share her people’s pain and press their flesh, or so we were told.

There was a sinister sub-text: she should also confess her “guilt” and her family’s “crimes” against the iconic Diana. To this end the Queen had to agree to give a television address, written for her by Downing Street and eulogising Diana “from the heart”, as she was obliged to say, even though everyone knew it couldn’t possibly be entirely sincere. Then, perhaps, it was felt the people might “forgive” her.

Blair had caught the people’s mood, in the spirit of the people’s princess — a phrase dreamt up for him for a nauseating churchyard speech — and became the people’s premier. The Queen had missed it, apparently.

Frears’s film gives a subtle account of that extraordinary mood, and of how the Queen had to recognise it and bend to it to survive. Her own mood, or mode, was the old-fashioned one of self-discipline and discretion, combined with compassion for her grandsons and a longing to protect them in privacy. “Quietly and with dignity. That’s how we do things in this country, and that’s what the rest of the world admires us for,” says Mirren as the Queen.

This placed the Queen on the losing side of what was seen as the Diana divide, much discussed at the time, a gulf between old and new, between self-restraint and self-expression, between feeling and duty, between privacy and publicity, between discretion and letting it all hang out. It did seem at the time as though the Queen had missed the post-Diana mood, or had underestimated it, and had been defeated by her daughter-in-law, even in death. But now I wonder.

This film is evidence of how shallow the Diana effect has proved to be. No longer does Diana appear as the unblemished victim, the standard bearer of feeling and truth against the massed forces of establishment repression. It’s true that Prince Philip and the Queen Mother appear as pantomime class stereotypes, perhaps with justification. But no longer does the Queen appear unfeeling or unsympathetic.

As Mirren said: “I think of all the things the Queen has gone through, the psychological traumas of the war years, 10 prime ministers . . . but she’s had the same values, the values of duty first, self last, and that constancy is extraordinary . . . and of course those values are the ones we cherish today.” And that is what she shows and makes us feel, in her magnificent, inspired portrayal of the Queen.

What a turn-up for the books. Frears and Mirren, like all talented artists, probably have their fingers instinctively on the public pulse — or, to put it another way, they are weather vanes: they know which way the wind of public sentiment is blowing. What’s more, the film’s producers must be convinced that this mood, and not the Diana mood, is what will make money these days. Le peuple le veut; the people want it. The royal family appears to be interesting, complex, human and forgivable.

Even the red carpet flummery, Balmoral kilts and stalking are gently treated, whereas in the Diana mood they might have been parodied viciously. This is all good news for the Queen and for royalists. And if Mirren’s responses are anything to go by, it is good news for the succession as well: Dame Helen is a big fan of Camilla.

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