* FTSE down 0.3 percent
* AB Foods knocked as Primark margins hit
* Barclays falls as the UK bank misses forecasts
By David Brett
LONDON, April 27 (Reuters) - Britain's top share index consolidated the previous session's sharp gains early on Wednesday, as investors sifted through a raft of earnings data from UK companies including Barclays, AB Foods and ARM Holdings.
By 0752 GMT, the blue-chip FTSE 100 was down 18.52 points or 0.3 percent at 6,050.84, having hit a 9-week closing high on Tuesday, albeit in light volumes, after the four-day Easter weekend and ahead of another four-day holiday weekend starting with the Royal Wedding on Friday.
The FTSE is now testing resistance levels of around 6,070, the level the index retraced from in early April. Technical analysts said that although investor sentiment is shifting more toward aggressive buying, volatility brought on by thin volumes could trigger reversals.
"Breakout to the upside at this current phase of the rally does not always indicate that the trend is getting stronger," James A. Hyerczyk, an analyst at Autochartist, said.
"It could also be indicating exhaustion as weak shorts cover and traders who missed the early part of the rally chase it higher."
There was a feast of corporate earnings on the menu for investors to devour.
Associated British Foods fell 5.8 percent as the company warned of flat annual earnings as squeezed consumer spending hit margins at its discount fashion retail chain Primark.
Barclays shed 3.4 percent, part of a weaker banking sector, as the British bank missed first quarter earnings forecasts.
Elsewhere, ARM Holdings gave up most of its previous session's gains, falling 3.4 percent despite the British chip designer posting a better-than-expected 34 percent rise in first quarter earnings, as investors banked profits.
ARM was one five companies to trade Ex-dividend, which knock 5.64 points off the FTSE 100 index with Centrica, Fresnillo, Smith & Nephew, and Tesco also losing their payout attractions.
UK GDP CONCERNS
Investors were cautious awaiting first-quarter UK GDP data at 0830 GMT. The forecast is for 0.5 percent growth, a modest recovery after a shock 0.5 percent fall in the fourth quarter of last year, which would mean the British economy has stagnated over the last six months, and with the UK government's austerity measures still to make their full impact.
"The worst case scenario today is that another negative print puts the country's economy back in recession," a trader said.
Investors will also cast an eye across the pond to the U.S., where later on Wednesday Federal Reserve Chairman Ben Bernanke will face the press in the first regularly scheduled news conference by a Fed chairman in the central bank's 97-year history.
Traders are speculating whether the Fed's QE2 programme could soon be wound up, reducing the supply of cheap money.
Back in the UK, artificial hip and knees maker Smith & Nephew slid 3.5 percent after U.S. firm Johnson & Johnson confirmed it is to buy Swiss medical devices maker Synthes Inc for 19 billion Swiss francs.
The U.S. company was previously seen as a potential suitor for Smith & Nephew.
On the upside, British temporary power provider Aggreko said it expected trading profit to be slightly ahead of 2010 after a strong start to the year helped revenues grow by 9 percent.
BP Plc gained 0.7 percent, among a firmer energy sector, after reporting a 2 percent drop in first-quarter profits, with traders saying the stock will be supported on valuation grounds.
"If BP's new model is successful, we believe it could start to close the gap between the share price and such asset-based valuations," Atif Latif, director of trading at Guardian Stockbrokers, said.
"With an aggressive asset sale programme continuing in conjunction with an increased activity in the exploration space the price anomaly should come back into parity." (Editing by Hans Peters)