My mother tells a story of a driver many years ago who successfully negotiated it in a cattle lorry, having been (correctly) told it was the shortest route to Eskdale. In those days it wasn't even metalled, and he had to stop and take two or three bites at each hairpin - going up
and down!
For myself, it reminds me of a few years ago on a Furness night rally one frosty evening. We were out in a Manta and couldn't make head nor tail of the cryptic route instructions (actually we had the wrong edition map

). Anyway, after sitting scratching our heads for twenty minutes at Eskdale Green we reasoned along the lines that if we were using sheet 89 then surely it
must go over Hardknott, so off we went.
As we got further up it got colder and icier, until eventually, about 1/4 mile from the top we rounded a left hand bend to find the road was a sheet of ice. Driver valiantly attacked it but we came to a slithering halt ten feet short of the dry tarmac above. Then we slid down backwards for 50 yards - in pitch dark with all 4 wheels locked up! In one of life's golden missed opportunities I'm ashamed to say that as we finally came to rest teetering on the brink I completely forgot to say "Hang on lads - I've got a plan."!
Fortunately all 4 wheels stayed on the road, and we were able to manoeuvre and pick our way back until we could turn round and get back down. We decided not to have another go and eventually caught up with all the other entrants who had (correctly) gone over Birker Fell instead, and thought it hilarious that we'd even tackled Hardknott in such conditions.
Of cours we didn't have speed cameras in those days - it couldn't happen today!
Definitely a road to treat with respect!