The FTSE 100 opened almost 200 points lower, down to 4869.61 at 0930, as the US downgrade continued to take its toll on stock markets around the world.

The blue chip index dropped by 199.34 points as trading got underway, following a night of market turmoil and widespread riots in the UK.

US financial stocks were hardest hit overnight as the Federal Reserve were rumoured to be mooting a further quantitative easing package.

Banks Barclays (BARC.L) and Royal Bank of Scotland Group (RBS.L) were hardest hit dropping 7.4 per cent to 162.35p and 7 per cent to 25.35p, respectively.

Tullow Oil (TLW.L) saw its share price fall 6.7 per cent to 888p, while asset manager Schorders (SDR.L) dropped 6.5 per cent to 1,368p. Sugar giant Tate & Lyle (TATE.L) saw its share price fall by 6.4 per cent to 509.5p.

There were no risers in early trading (at 0927).

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