It is an amazing feat in the 21st century that Queen Elizabeth II, a small woman in her late-eighties, should be one of the most recognisable people on the planet.

Her voice is redolent of another era, her interests are esoteric to many of her people, her opinions on anything from the weather to politics are almost entirely unknown, and her whole life has been lived without ever mingling on equal terms with anybody, except for one heady evening in 1945 when she slipped out of Buckingham Palace incognito to join the crowds celebrating the end of the war in Europe. The world has utterly, irreversibly, and radically evolved since she ascended the throne in 1952 and yet, in an era of instant celebrity, she remains, more popular than ever and seemingly largely unchanged: a bastion of certainty and comfort to the British and many other people during uncertain times.

On 9th September 2015, she will beat Queen Victoria's record and become the longest-reigning monarch in British history. The question is: How secure is the British Royal Family? How much depends on the person of the Queen herself, and how much on the institution?

To answer these questions, Royalty Inc. will combine a history of the British Crown's evolution thorugh the modern age with a journalistic peek behind the curtain at the machinery that sustains the Windsors today. Written by the Guardian's former Royal correspondent, its line will be neither royalist nor republican. Instead it will take a clear-eyed look at a host of issues, including the future of the Commonwealth, the Monarchy's role in the British constitution and class system, Prince Charles' notorious 'black spider memos', the true scale of the Royal finances, the legacy of Diana, and the problems and pressures faced by any heir to the throne in the future.