Far from unique to BoJo. This is a wildly successful strategy, which also explains the outrageous and obvious lying (e.g. in front of dozens of press saying "there's no press here"). It's not new. Many of the internet era populists currently so successful have used it. Trump was the first time I saw it, but perhaps it goes back further.
Each and every time he lies, misremembers and drops in a search term he makes it harder to disprove as both sides get reported. The original story and the the reports of the use of the lie. Both in the respected media, not just a random blogspot. Frequently they're both running at the same time.
With Trump the Democrats and media spent to much time "fact checking" to see the strategy. Ours have done no better with BoJo, despite seeing it played out so successfully in the US.
It completely burns the post-war expectation that politicians be honest, and plays all sides as effectively.
I'd love to know where it really originated.