It should come as no surprise that Rupert Murdoch has decided to step down from the top of his media empire. Yet the news that the 92-year-old, no longer in the best of health, will not die in the job, as he always suggested he would, came as a huge shock.

After a lifetime spent transforming the relatively small Australian print newspaper business he inherited from his father into a global corporation, which spans one of the biggest newspaper businesses in the UK and one of the most controversial television channels in the US, he stands down ahead of two hugely important elections in both his adopted homelands, Britain and the US.

The timing of his decision to step down, or rather “transition” into an emeritus role in his words, cannot be coincidental. It will be minutely analysed over the weeks ahead.

But it is not too soon to consider now what his decision means, not just for his business but for the world of media and politics that he has done so much to influence. If the world before he took over a struggling tabloid newspaper in a grey but proud postwar Britain is the time we will call BM, “before Murdoch”, what will the morning and the new epoch, AM, or “after Murdoch”, look like?