An upbeat assessment of the UK economy from a leading central banker failed to offset uncertainty over US monetary policy, with the FTSE-100 Index climbing just 14.1 points to 6571.5.
Ripples from the US Federal Reserve's recent decision to continue pumping $85 million (£53m) a month into the world's biggest economy left traders wondering over the timeline for tapering the stimulus.
Lack of progress on raising America's debt ceiling and the US central bank's gloomier outlook for growth also dampened enthusiasm for stocks.
Craig Erlam, market analyst at Alpari, said: "Debt ceiling negotiations and the Fed are continuing to weigh on indices. The uncertainty surrounding both these events has left investors feeling rather risk-averse."
There were mixed signs from Europe as German business optimism, though improved, was slightly below expectations, while reports elsewhere indicated the European Central Bank remained wedded to stimulus measures. Markets were up in Germany and France.
The lethargic mood in the City came despite Bank of England rate-setter David Miles saying recent UK economic data is "overwhelmingly positive".
Mr Miles also dampened speculation over interest rate hikes, saying that while the Britain's performance was improving, recovery remained "embryonic".
In a thin day for corporate news, miners were among the heaviest top flight fallers on softer commodity prices. Fresnillo was 42p lower to 971p, while Randgold Resources waned 128p to 4493p.
Market share figures for the UK's supermarkets contained more bad news for Tesco, which saw its share fall to 30.2% in the 12 weeks to mid-September, from 30.9% a year earlier.
Tesco shares were 2p lower to 374p, but Sainsbury's was 2.8p higher to 398p after its market share grew to 16.6% from 16.4%.
Number four player Morrisons fell 1.7p to 287.6p as the figures from Kantar showed its market share fell from 11.4% to 11.1%.
Outside the top tier, coal miner Hargreaves Services edged up 5.5p to 814.5p even though annual profits were wiped out by its closure of the Maltby deep mine in Yorkshire.
The group, which has been busy buying surface mines, said coal will play a vital part in Britain's energy mix for at least the next decade. Losses of £49.6m in the year to May 31 compared with profits of £30.8m a year earlier.
The biggest FTSE-100 risers were Sports Direct, up 15p to 709p, Coca-Cola HBC up 39p to 1864p, Barclays climbing 5.1p to 271.4p and Vodafone up 4p to 213.1p.
The biggest fallers on the FTSE-100 were Carnival, down 134p to 2258p, Fresnillo off 42p at 971p, Randgold Resources down 128p to 4493p and Anglo American down 28p to 1545.5p.