A trader monitors the screen on a trading floor in LondonBy Toni Vorobyova LONDON (Reuters) – UK stocks retreated on Tuesday, with news of steep client outflows at Ashmore hitting other asset management shares and exacerbating concerns about the strength of the upcoming earnings season. Ashmore tumbled 11.7 percent, on track for its biggest one-day drop in five years, after saying volatility in core emerging markets had spooked investors, who withdrew a net $3.5 billion from its funds in the last three months of 2013. The drop in mid-cap Ashmore helped push the FTSE 250 down 0.7 percent, and the negative sentiment also reverberated around its blue-chip peers. Aberdeen Asset Management, which is due to issue a trading update on January 16 and which also has a strong focus on emerging markets, dropped 1.7 percent.