The London market slipped in afternoon trading after the Bank of England failed to buy as many government bonds as it planned.
The FTSE 100 Index fell 13.4 points to 6837.9, after the Bank bought £1.12bn of government bonds on Tuesday as part of its new programme of quantitative easing, falling below its plan to purchase £1.17bn. The FTSE 250 Index was 12 points down at 17675.4.
The shortfall fuels fears the central bank may not be able to complete its £60bn six-month programme. Bond buying from financial institutions frees up cash for them to make other investments in other assets such as shares.
On the London market, insurance giant Prudential posted better-than-expected profits in the first six months of its year – up 9% to £2.06bn ($2.69bn), driven by the growing number of savers in Asia.
The City had expected the insurer to turn in operating profits of £1.88bn. Shares lifted 25p to 788.5p.
Media distribution company Entertainment One rejected a £1bn takeover approach from ITV, as its 236p-offer "fundamentally undervalues the company and its prospects". Shares in Entertainment One jumped almost 7%, or 14.5p to 232p, while ITV edged up 1.2p to 200p.
In afternoon trading the biggest risers on the FTSE 100 Index were Rolls-Royce Holdings (+25p to 788.5p), Randgold Resources (+160p to 8655p), Fresnillo (+29p to 1986p), Prudential (+19.5p to 1411.5p) and Legal & General (+2.4p to 208.4p).
The biggest fallers on the FTSE 100 Index were Standard Chartered (-13.3p to 654.9p), International Airlines Group (-6.1p to 401.1p), Taylor Wimpey (-2.3p to 152.3p), Berkeley Group (-39p to 2611p) and Schroders (-40p to 2687p).
In afternoon trading the biggest risers on the FTSE 250 Index were G4S (+33.9p to 229.5p), Paysafe Group (+28.9p to 420p), Entertainment One (+14.5p to 232p), B&M European Value Retail (+9p to 272.9p) and Keller Group (+21p to 883p).
The biggest fallers on the FTSE 250 Index were Regus (-16.6p to 304.4p), NCC Group (-16.2p to 328.6p), Tullow Oil (-7.2p to 213p), JRP Group (-3p to 96p) and Amec Foster Wheeler (-15.5p to 505.5p).