Liability insurance

Hi all new here , I’ve just started driving trucks again after a few years lay of , Being self employed I was wondering what sort of insurance would I - might need, I have public liability insurance for other work I do but not sure if this would cover me to drive trucks
I’ve heard I would be covered buy who ever’s truck I may be driving at the time, but suppose I was say backing an artic up some where in the dark and chucking it down with rain and I backed into a bollard and knocked it over and smashed a back light on the trailer as much as it may be may fault would I be liable for the damage caused .

Had a look on line for a liability insurance for self employed HGV drivers to no avail