Presiding officer Simone Evans improvised after being unable to gain access to the Royal British Legion branch in Buckie, Moray.
Polling station notices were put up in the windows of her Ford Galaxy, with the ballot box on the front passenger seat and voters given privacy to cast their vote in the back seat.
Two early voters turned out to exercise their democratic right in the back of the car before staff turned up to open the building.
Moray’s depute returning officer Moira Patrick said: “She did exactly what all our elections staff are trained to do in the event of not being able to gain access to a polling place for whatever reason.
“It is part of their training, but as far as I can recall this is only the second time it has ever had to be put into practice.”
Moray Council said it was unclear why the building was not accessible in time for the polls opening at 7am.