Top Gear is one of the BBC's most popular programmes and without Clarkson it is nothing. He knows this, and so do the BBC. It does say that this is only temporary due to an investigation, and we can't even be sure what exactly happened or how serious it was. I'm pretty confident that the show will continue.
There's this talk of Clarkson being sacked because he was already on a "final warning" but he's had that sort of warning before and gotten away with far worse things (even though a lot of those things were exaggerated).