Share prices look to end the week on a jittery note as Gadaffi troops launch an assault on the Libya oil port of Ras Lanuf, Japan suffers a devastating earthquake and Chinese inflation and industrial production exceeded forecasts in February.
Adding to the gloom on the economic front UK February factory gate inflation hit a 26-month high in due to surging oil prices, adding upward pressure to interest rates.
Fourth-quarter construction output was revised up slightly, with a minimal impact to GDP.
Already unnerved by a big sell-off in the US overnight in the wake of an unexpected increase in jobless claims and continuing concerns over eurozone debt problems, the FTSE 100 index had fallen a further 40 points to 5,805 by 10am and the Mid-250 index had lost 94 points to 11,428.
Insurers were particularly badly hit by the latest huge earthquake in Japan. Legal & General at 115p, Aviva 450p and Prudential 720.5p, shared falls of between 3p and 14p.
Among the re-insurers Catlin shed 15p to 351p and Amlin 16p to 389p
Miners recouped recent losses on China's buoyant industrial production figures with Rio Tinto rallying 55p to £39.87 and Xstrata 8.5p better at £13.57.
Tullow Oil at £13.65 and Aggreko £14.06 recouped around 15p of yesterday's setbacks that followed cautious updates.
Favourable comment on yesterday's figures and online expansion plans supported William Morrison at 287p, up 2p, but competition worries overshadowed Ocado, 8p lower at 198p.
A positive review from JP Morgan strengthened Babcock at 570.5p, up 5p andSports Direct attracted fresh support after recent refinancing, 3p firmer at 183p.
FirstGroup reversed 16p to 344p as its US business underperformed and remained challenging, but J D Wetherspoon spurted 13p to 444p in response to results in line with expectations.
Dixons Retail softened 0.48p to 17.080p as Citigroup downgraded its rating to hold from buy.