Oh yeah, I forgot the other one yesterday.
Exactly the same situation as the other one, Prius sat in lane two bimbling along in their own little world, first lane clear as far as the eye can see, third lane rammed. I'm sat in the first lane with the cruise control set at an indicated 75mph (so doing just under 70mph in actuality).
The Prius driver then started drifting across into the first lane as I was along side him. I was watching for this as it happens occasionally; I guess some people aren't expecting someone on the left / aren't observant, and some decide to "teach me a lesson". I sounded the horn to alert him to my presence and he swerved back. He then seemed to take this as an insult to his masculinity (in a Prius), blasted the horn several times as I passed, then booted it (did I mention he was in a Prius?)
He pulled back alongside me and started to nose ahead. I figured, if he got in front of me then who knows what he'd do next; struck me as we'd soon both be on the hard shoulder with him claiming whiplash. So I accelerated a little too, just up to an indicated 80, to keep him from carving me up. Fortunately, the next vehicle in front of us both was a lorry also lane-hogging the second lane, so I sailed merrily underneath him too and the Pious had to brake, that was the last I saw of him.