Alan Greenspan has become the financial equivalent of a Las Vegas betting line, his assessment of the chances of recession accepted as the official line in laying down bets on the economy.

The former chairman of the Federal Reserve cast a bearish tone on markets today, when he told BBC Radio 4 that the odds of a recession have increased.

"The danger of a recession has obviously risen, but in my judgment and I suspect looking at the forecasts of most American economists, it's still less than 50-50," Greenspan said. "It's less optimistic than one would like."

Greenspan, who is giving interviews in Britain to promote his book, The Age of Turbulence: Adventures in a New World, has made similar comments in recent days, including on NBC's Meet the Press program on Sunday.  

Still, the betting line has been evolving: Earlier this month, he said the chances were greater than 1 in 3. In May, he said that the odds that the United States would avoid a recession were 2 to 1. In March, he helped spark a sell-off in the markets by saying that the chances of inflation were less than 1 in 3.

"I'm not forecasting that we're about to get a significant recession in the U.S. or the U.K.," Greenspan said. "All you can basically know is whether the probabilities are increasing or decreasing.''  Greenspan, an unofficial adviser to Gordon Brown, will meet with the British prime minister this weekend, the BBC said.

Greenspan "is right in pointing to the risks of a U.S. recession," Matthew Sharratt, an economist at Bank of America told Bloomberg News. "The clear risk that consumption may soften is a worry for the U.S.''