Carson narrowly beats Donald Trump in new poll
A retired neurosurgeon has knocked Donald Trump off top spot in the Republican presidential campaign.
Ben Carson takes a narrow lead in in a New York Times/ CBS News poll, ousting the New York businessman who has led the pack for nearly four months.
The news comes on the eve of the third TV debate for Republican contenders.
The next-ranked candidates are Marco Rubio, Jeb Bush and Carly Fiorina but they are a long way behind.
The conservative Mr Carson, who has expressed extreme views on a range of issues, has 26% of Republican primary voter support, according to the telephone poll of 575 voters.
His lead of 4% over Mr Trump is well within the 6% margin of error.