That prompted me for a research.... The google search immediately led to your conclusion. But there was a contradiction to that ... They say Democracy existed in 'BC' era
Forget that .. There is a big fight around the world regarding this issue...
http://www.nipissingu.ca/department/history/muhlb...stdem/chronpag.htm
So as far as modern demoracy system is taken into consideration, Brits were not democratic while under Queen. So it has to be US. If the criteria of democracy is britains', then even Athens/greece had democracy in Bc's