* FTSE 100 down 1 percent
* Aberdeen leads emerging market sell-off
* Pearson hit by downgrades after profit warning
By Tricia Wright
LONDON, Jan 24 (Reuters) - Britain's top shares sank to 1-1/2 week lows on Friday, with stocks exposed to emerging markets among the biggest fallers, knocked by a rout in Latin American currencies.
Aberdeen Asset Management shed 5.5 percent, the FTSE 100's top faller, while peer Ashmore was among the steepest FTSE midcap decliners, off 4.7 percent, suffering from their heavy exposure to emerging markets after Argentina's central bank gave up its battle against the currency's decline.
"Emerging markets exposed stocks are under pressure this morning as the currency situation in Argentina is going from bad to worse," said Mark Ward, head of trading at Sanlam Securities.
"The risk of spillage into Brazil and other major trading partners is increasing, as is the capital flight risk for Argentina," he said.
The FTSE 100 was down 69.18 points, or 1 percent, at 6,704.10 points by 1154 GMT, trading at its lowest level since Jan. 14 and on course for its biggest one-day percentage drop this year. The index shed 0.8 percent on Thursday, hit by disappointing data from the United States and China.
Brewer SABMiller and temporary power provider Aggreko, which have exposure to Latin America, saw respective losses of 2.6 percent and 2.9 percent on Friday.
It was a quiet day for corporate earnings, but Pearson was a big faller, off 2.6 percent, as analysts cut their target prices for the publisher following Thursday's profit warning.
Despite this, and warnings from other firms including oil major Shell as the European reporting season gradually gets under way, some investors take the view that the earnings will justify high valuations after a strong 2013.
"We do think that the earnings will come through ... (Valuations are) only lofty compared to the last five years which could be the worst in most people's careers," said Peter Sullivan, head of European equity strategy at HSBC.
"We're expecting double-digit earnings growth this year and next. How can we see that when the UK economy is only just emerging from recession? I think the key is that momentum of economic growth is positive across the world."
The FTSE 100 currently trades at 13 times 12-month forward earnings - the highest since late 2009 and far above the 5-year average of 10.8 times, Thomson Reuters Datastream shows.