The leading shares were flat at midday on Wednesday, recovering from losses in a rally led by energy stocks <.FTNMX0530> as crude prices rose and Wall Street was indicated to open higher.
The index fell earlier on concerns over global growth and corporate earnings, with low volumes contributing to the volatility.
Oil prices rose mainly on a technical rebound and ahead of U.S. inventories that could show a drop for a third week, easing concerns over the level of stocks held by the world's largest oil consumer.
By 1123 GMT, the FTSE 100 index <.FTSE> was down 1.42 points, or 0.03 percent, at 5,662.64, having bounced from a session low of 5,625.60 in volume of under 20 percent of the 90-day daily average.
U.S. index futures were around 0.4 percent higher, pointing to a recovery on Wall Street after falls in the previous session, with traders looking ahead to the release of minutes from the last Federal Open Market Committee meeting (FOMC), due after the London close at 1800 GMT.
"I don't know if we'll find anything earth-shattering in there. But there is a hope we'll get a clearer picture on the FOMC's decision-making process on QE .. and on what the hurdle is for a further large-scale asset purchase programme," said David Morrison, market strategist at GFT Global.
Weakness in mining stocks <.FTNMX1770> continued to drag on blue chip sentiment, with the sector knocked by a cautious Credit Suisse note as the broker cut its forecast for metals and oil prices.
"With the relief rally now mostly complete, the next move in commodity prices is likely to again be driven by developments in global growth ...This suggests to us that the balance of near-term risks to the industrial commodity complex is to the downside, particularly in light of the speed and magnitude of the recent bounce," Credit Suisse said in a note.
Chemical stocks were also under pressure from broker comment. Johnson Matthey shed 2.7 percent, while Croda shed 1.5 percent, as UBS downgraded its rating for both British firms to "neutral" from "buy" on valuation/outperformance grounds.
"We like and continue to like the UK chemicals space for fast growth, defensive positioning and high tech, genuine specialty nature. That being said, the quality names have now witnessed an unprecedented relative rerating…which we reflect in our ratings," it said in a note.
British luxury brand Burberry was the biggest individual casualty, down 5.7 percent after the company reported a slowdown in quarterly sales growth as trading conditions worsened.
Lloyds Banking Group was also under pressure, down 0.1 percent as Liberum Capital double downgraded the lender to "sell" from "buy" on concerns over the bank's potential exposure to litigation over manipulation of the LIBOR rate and the worsening economic environment.
Lloyds has outperformed Barclays , which has lost its chairman and chief executive due to the LIBOR scandal, by around 25 percent since June 1, and is faring about 15 percent better than Royal Bank of Scotland .
Barclays shares lost 0.4 percent while RBS added 1.1 percent.
Among other financials, insurer Aviva was in demand, up 1.6 percent as it completed the sale of stake in Dutch firm Delta Lloyd , with traders citing the impact of an upgrade in rating from Morgan Stanley.
ICAP rallied from earlier falls, adding 1.4 percent as the world's largest derivatives broker brought forward plans to slash 50 million pounds of annual costs to counter a trading slowdown that forced revenues down 9 per cent in the last quarter.
(Reporting by Jon Hopkins; Editing by John Stonestreet)