The FTSE 100 Index closed flat at 5806.7 after figures revealed the US economy grew at an annualised rate of 2% in the third quarter, better than the 1.8% rise forecast by analysts on Wall Street due to strong consumer spending.
The figures managed to lift some of the gloom caused by tech giants Amazon and Apple last night as the pair revealed they had been hit by the cost of launching new products such as Apple's iPhone 5 and Amazon's Kindle business.
A string of disappointing results in the US has shaken traders in the last week, including updates from machinery giant Caterpillar, clothing company VF Corp and aviation firm Boeing.
The pound was down against the US dollar at 1.60 as the greenback strengthened on the back of the GDP figures. Sterling was also off against the euro at 1.24.
However, Ishaq Siddiqi, market strategist at ETX Capital, warned the US figures did still suggest the recovery on the other side of the Atlantic was weak.
He said: "We would caution against getting too excited about these figures just yet and would wait for further signals of growth before turning optimistic on the US economy."
In London, chip designer ARM Holdings, whose products are used to power many of Apple's devices, fell 1%, despite posting a strong set of its own results earlier in the week.
The Cambridge-based company, which saw shares drop 8.5p to 656.5p, is heavily influenced by the performance of Apple despite supplying parts to a range of other tech firms' products.
Shares in FT publisher Pearson were 9p higher at 1221p after it said it was in discussions with Random House's German owner Bertelsmann about a merger involving its publishing arm Penguin.
The move would bolster the companies in the face of a changing market - driven by the rise of the ebook from the likes of Amazon, Apple and Google.
And Anglo American shares jumped 4% higher after the mining company announced plans for the departure of chief executive Cynthia Carroll following more than five years in the role.
The rally for the stock, which climbed 76p to 1933.5p, reflected hopes that a change at the top will inspire an improvement in fortunes for the share price and profitability.
However, the downbeat sentiment surrounding the US results season hit other mining stocks, with Kazakhmys at the bottom of the FTSE 100 Index, off 21.5p at 714.5p, and Vedanta Resources 9p lower at 1127p.
The biggest Footsie risers were Anglo American up 76p at 1933.5p, Evraz ahead 4.3p at 239.7p, Weir Group up 29p at 1717p and Burberry ahead 19p at 1153p.
The biggest Footsie fallers were Kazakhmys down 21.5p at 714.5p, Prudential off 16p at 837p, Wood Group down 15p at 833.5p and Standard Life off 4.2p at 284p.
