The horse, called Raisa, notoriously belonged to the Metropolitan Police, was loaned to former red-top editor Rebekah Brooks and was ridden by David Cameron.
There encapsulated in one totemic anecdote is the whole story of the too-close and possibly corrupt relations between media, police and politicians.
Never mind dozens of arrests, extraordinary testimony at the Leveson Inquiry and corporate upheavals at News International. The horse is the story.
It is a sound bite that makes the complex web of allegations comprehensible to people outside the media and Westminster bubbles. As a pub story, a viral joke and a satirist's dream it is uncontrollable.
Just as a duck house became the cliche for the MPs' expenses scandal, so Raisa has become the horse of the apocalypse for those involved in the unfolding scandal.
The hound - Rosie the bulldog - however, has a very different story to tell.
She belonged to Harry Redknapp, the man who is almost certainly the next England football manager. Rosie, a court was told, lent her name to the offshore bank account which 'Arry was accused of using to defraud the taxman.
'Bad dog - I've told you not to open bank accounts in my name' was one of the thousand cartoon captions and quips launched by the revelation. Simultaneously, pictures showing the much-loved Redknapp walking his pet along the seafront were shrewdly placed in the media.
Rosie, like Raisa now sadly deceased, added to the gaiety of the nation and to the popularity of Redknapp. Unlike Raisa, her legacy was entirely benign.
Harry was acquitted, his popularity enhanced, as the world chuckled at the story of one man and his dog.
They are cautionary tales for PR gamblers contemplating staking reputation on horses or dogs. As the bookies say, you can lose as well as win.
Ian Monk is founder of Ian Monk Associates and a former executive at the Daily Mail and The Sun.