Size wiring for Ring Flood cam

Hi, we just moved house and I'm going to refit our Flood light cam, in our previous home I'd used a thick extension cable to wire it up, in the new house I would like to use a much thinner cable, can anyone tell me the minimum cable rating and size I need when wiring it back up, I will be fitting a 13amp plug on the end to plug into a wall socket. Many Thanks