They really did just drive a tank through London.
Done partly as a show of support and partly as a good old fashioned publicity stunt, the UK political blog Guido Fawkes has driven a tank to the BBC to symbolically deliver (almost) 1 million petition signatures to reinstate Jeremy Clarkson as a Top Gear presenter. The petition hadn't quite actually reached a million signatures by that point, but was only a few thousand shy. And this little stunt seems to have given it a push as well, since at the time of this writing it has 1,015,702 signatures.
The signatures were "delivered" (obviously not really, as all of them are digital) by a fake Stig wearing a hilariously bad fake costume, because apparently they blew the whole budget on getting the tank. There has been no response from the BBC, and frankly it is unlikely to change anything. The BBC knows its own viewership numbers, and knows how popular Clarkson is, probably better than the folks at Guido Fawkes do, and this was therefore already taken into account. Clarkson himself has even come out saying "protesting never works", but we can still hope.