Robotic combat was started in '94 in the US by Marc Thorpe with the creation of Robot Wars. RW-UK started in '98 and RW-US '98 was canceled due to a very nasty company who sponsored it.
The competitors attempted to make their own event but were stopped by lawsuits just before the competition. RW-US attempted to start up again but they met strong (and well-funded) competition from the new event, BattleBots, which was/is run by two former competitors.
RW-US has been resurrected, the first season was filmed in London a few weeks ago by the same production company that does RW-UK (so it should be similar.) RW-US as well as RW-UK episodes will air on TNN starting next week.
For a more thorough history check out:
http://www.robotcombat.com/history.html
Dan