* FTSE closes down 0.02 percent
* Aggreko gains on positive outlook
* AB Foods drops as it cuts Primark margins to hold mkt share
By Joanne Frearson
LONDON, April 27 (Reuters) - Britain's top share index ended flat on Wednesday ahead of Federal Reserve Chairman Ben Bernanke's news conference which could provide clues on the Fed's future plans for its monetary policy.
The blue-chip FTSE 100 was down 1.2 points or 0.02 percent at 6,068.16, having hit a 9-week closing high on Tuesday.
Volume was only 87.6 percent of the 90-day average.
The index had earlier been as high as 6,089.40 buoyed by hopes cheaper money would raise demand for equities after the prospect of a UK interest rate hike in the short term decreased following GDP data.
"UK GDP had kept the FTSE 100 up, because it was not worse than expected," Mark Priest, senior equities trader at ETX Capital in London, said.
"Investors are cautious ahead of Bernanke. It depends exactly what he says, everyone is waiting to hear his plans on quantitative easing and how he sees the economy heading."
The Fed's ultra-easy monetary policy has buoyed demand for riskier assets and comments from the Federal Reserve could shed light on the central bank's future plans for interest rates and quantitative easing.
Banks featured among the worst performers as investors sold out of riskier assets. Barclays fell 4.8 percent after first-quarter profit missed forecasts.
In other earnings news, Associated British Foods dropped 5.8 percent after the food producer said it will cut its margins at its Primark retail chain and absorb higher costs to maintain its market share, prompting analysts to trim their full-year earnings forecasts.
Aggreko jumped 4.4 percent after the British temporary power provider said it sees trading profit slightly ahead of 2010.
ITV lost 3.9 percent after Barclays Capital downgraded its rating for the British commercial broadcaster to "equal-weight" from "overweight".
FTSE TESTING RESISTANCE
The FTSE 100 was testing resistance levels of around 6,070, the level the index retraced from in early April.
David Jones, chief market strategist at IG Index, said the FTSE would need to break through the year's high at around 6,105 before fresh momentum comes into the market.
Meanwhile, companies trading ex-dividend knocked 5.64 points off the FTSE 100 index, with ARM Holdings, Centrica, Fresnillo, Smith & Nephew, and Tesco all losing their payout attractions. (additional reporting by David Brett; editing by Elaine Hardcastle)