No. There is no starter motor on these. The engine is turned over by the motor/generator which is incorporated into the transmission. If the hybrid battery fails completely, the car will stop as there is no way that it can turn the engine over. There is no conventional starter motor on these or the Toyota hybrid cars, basically the hybrid battery powers the motor/generator and it in effect, bump starts the engine when it needs to.

Once the engine has started, it will power the front wheels and then the motor switches into a generator mode (hence it's name) to power the rear wheel motors and also recharge the hybrid battery if needed.

Also, there's no alternator to charge the 12volt auxiliary battery. This is charged by the hybrid battery too by clever voltage sensing. If the 12volt auxiliary battery is flat, the car won't go either. You can jump start the 12volt battery if it has too low a voltage to wake the system up (see your manual for instructions), but if this doesn't work, get it recovered to a dealership, DO NOT GO ANYWHERE NEAR THE HYBRID SYSTEM. It's very unlikely the hybrid battery will just fail without warning. If you go poking around in the boot there is 288 volts DC and at the inverter under the bonnet 650 volts AC so more than enough to cause a serious case of death.

Is this a hypothetical question, or are we witnessing one of the very rare Toyota hybrid failures...if so the daily and motoring rags should be informed, bring on some meaningful balanced reporting..;)