Her Majesty still riding high at 87

While some of her hectic schedule has been quietly adjusted, with her children and grandchildren playing a more significant part in royal service, Her Majesty still has a packed diary.

This week, she faces criticism for hosting former IRA Commander Martin McGuiness at a state banquet in Windsor Castle in the further pursuit of peace. But she thinks now is the right time.

It is part of the first ever state visit to Britain by Irish President Michael D Higgins

Last week she was on a high profile visit to Pope Francis in Rome and a few days before that, was photographed riding round the grounds at Windsor Castle.

The Queen has been riding since the age of eight and will be 88 in less than a fortnight. That is 80 eventful years and apart from teaming up with a favourite pony rather than a bigger horse as a concession to a dodgy knee, she shows no signs of giving up her equestrian passion.

For many years her favourite Trooping of the Colour horse was Burmese, given to Her Majesty by the Royal Canadian Mounted Police. The horse was seven, had been trained in Ottawa and was ready for her first Colour parade that same year.

The Queen rode Burmese until the horse was retired and she has attended the parade in a horse-drawn carriage ever since. Elizabeth II is one determined lady.

Which is how she faces the life of duty to which she committed so long ago in Africa on her 21st birthday after the death of her father George VI. Referring to monarchs of old, she said: "Through the inventions of science I can do what was not possible for any of them. I can make my solemn act of dedication with a whole Empire listening. I should like to make that dedication now. It is very simple.

"I declare before you all that my whole life, whether it be long or short, shall be devoted to your service and the service of our great imperial family to which we all belong. But I shall not have strength to carry out this resolution alone unless you join in it with me, as I now invite you to do: I know that your support will be unfailingly given.

"God help me to make good my vow, and God bless all of you who are willing to share in it."

What a breathtaking promise, and one she has kept in full measure ever since. Through the changing scenes of all our lives, the Queen has stayed true to that pledge yet managed to adapt to life in the modern world, the world of her children, grandchildren and now the young great-grandchildren.

For instance, she long ago realised that she must embrace the publicity culture in the new, global era. And remember, she originally had grave doubts about even allowing cameras into Westminster Abbey for her Coronation.

Thank goodness she was persuaded and so we have that historic and treasured, grainy footage which marks the glorious beginning of this great reign.

Talking of great reigns, QueenVictoria's was of course the longest, lasting for 63 years and 216 days. But at the beginning of this week, our Elizabeth II had reigned for 62 years and 60 days. So next year, she is set to overtake the landmark of her great-great grandmother, Victoria. But while this Queen has always said she will not abdicate, she is not really interested in any race to top that poll.

She just believes that monarchs are for life, for better or for worse, and she has never wavered in that.

In between incomparable service to nation, Empire and now Commonwealth, she has brought up a family of four, rejoiced in eight grandchildren and now dotes on newcomers Prince George and Mia, the daughter of Zara Phillips and her husband Mike Tindall.

Apart from constant visits and daily duties, boxes of papers and the political scene are still a massive commitment. But that is nothing compared to the stress caused by the divorces of three of her children which so grieved her.

She has worried quietly about the health of her 93-year-old husband, the Duke of Edinburgh, the only boyfriend she ever had and who, through the years, has had to deal with spells of undeserved animosity.

She admits that her deep Christian faith sustains her through those days.

And now, we see the Queen's close relationships with the girls who have come into the family, Sophie Duchess of Wessex, Catherine Duchess of Cambridge and most significantly, Camilla, Duchess of Cornwall. The woman who could – and should as wife of the heir – be our next Queen.

Despite the years of cold antagonism, Camilla has won, if not hearts, then respect. And now, she and Charles along with William and Catherine – currently representing her in New Zealand and Australia complete with George on first official royal engagement – are very much the future.

None of which is a hint that the Queen is handing over the task she inherited all those years ago.

She has just agreed to job-sharing in the best way of all – still carrying the baton while preparing to one day pass it on.

As another big birthday approaches, we honour this lady who continues to be such an active force in our nation and the steadying anchor in our common life.

She is relaxed, smiling, still busy but at ease.

God bless Elizabeth, our Queen.