When I was driving today an electrical fault popped up showing a yellow icon of the battery. After another few miles, a red warning light Drive System Malfunction popped up and the car lost all power. I immediately turned off the engine and restarted it. It started fine but after I drove about 10 yards the drive system malfunction kicked in again and lost power. This happened a couple of times. I eventually managed to crawl it (keeping under 10mph) to a safe place to stop. Does anyone have any ideas what the cause is?