There are certain cases where Insewerance is not required.
If you lodge a HUGE amount of money with Loyds of London you can drive without cover, it`s how the Royal family etc are able to drive.
No company would ever cover the likes of Prince Harry, or even some rich arabs etc, as the potential losses if sued could destroy them, so they lodge a wad with Loyds to cover any third party losses and drive away,