Whether Royalist or Republican, none would doubt the incredible life of our reigning monarch.

The Queen’s Diamond Jubilee celebrations have begun in earnest as the nation gears up for one of the biggest parties of all time.

Last night’s exceptional documentary by Andrew Marr explored the life and achievements of Elizabeth II. Sixty years after the death of her father led to her accession, the first in his three-part series took us behind the scenes of our indefatigable Queen’s life.

Marr is the BBC’s go-to man when it comes to weighty, political issues. He brings a gravitas to his work that others, like Jeremy Vine or Peter Snow, somehow fail to muster. Intelligent, erudite and engaging, he orchestrates the facts with forensic attention to detail. Skilfully, he lets the story tell itself and willingly plays second fiddle.

The Diamond Queen was a captivating programme that saw the BBC give of its best. The archive footage was interspersed with telling interviews from historians and others.

Marr was given unique access to a starry cast, with former Prime Ministers Tony Blair and John Major joining the present incumbent, David Cameron, in paying tribute.

Marr gave us fascinating insight. He got under the skin those Prime Ministers and other politicians to paint the Queen as a remarkably good listener, viewed by some elected leaders as a quasi-therapist.

There were similarly fine interviews with the Queen’s children and grandchildren, who offered fulsome words of praise for a woman who inspires affection and devotion among her many subjects. Princes William and Harry were particularly good interviewees.

The Queen’s life has, of course, been extraordinary and Marr’s programme helped us to understand some of the reasons why.

There was delightful footage, for instance, of an exquisite Wendy House that was her playroom as a girl. While some youngsters yearn for a small, foot-high wooden structure into which to place dolls, the Queen was given a life-sized home complete with thatched roof and furnishings.

The Queen was painted as a good listener who is kind and wise. She was shown to be formidably bright and remarkably well-disciplined. Prince Andrew suggested there were only three people in the country who really knew what was going on: the Chief Secretary to the Treasury, the Prime Minister and the Queen. Her appetite for reading reams of Government documents was plain.

Other aspects of her personality were also clear. Our Monarch was painted as a lady with a good sense of humour, ever-able to see the light in any situation. She was shown to be a smooth operator, a discreet woman able to charm and conceal, to read out her Government’s intentions before Lords, Ladies and Gentlemen without offering any idea of her own opinions.

The importance of the Queen’s experience, of her links to great events in world history, was emphasised by Marr. No other figure on the global scene has held centre stage for so long, no one else has met as many world leaders nor banked as much experience.

Former Foreign Secretary Douglas Hurd painted her as a calming but powerful non-confrontationalist.

However, the over-riding impression was of a lady wedded to duty. The Diamond Queen was a remarkable programme that reminded us of the debt we owe to our long-serving Monarch.

She articulates the emotions of the common man. She is devoted to serving her subjects.

Andy Richardson