Jacked up - if the handbrake works as it should on each side, I wouldn't worry until the next inspection is due. Keep an eye on the fluid level.
A mate of mine drove his Midget with the handbrake seized on one side, not very far, but the heat was so great that it melted the rubber covers on the wheel cylinder, and melted the piston seals, so all the fluid ran out and his brakes failed. No damage other than ego, but I've never seen such a mess before or since. The rubber had turned to charcoal.
