London Stock Exchange is one of the heaviest fallers in the FTSE 100 after the exchange operator was forced to suspend trading for more than three hours following a technical hiccup this morning.It had already come in for selling ahead of the shutdown as analysts fretted over how the Dubai debt situation will affect the 20.6% stake held in the company by Borse Dubai. The government owned Dubai World, which has debts of $59bn, has asked creditors if it can delay debt repayments due next month until May of next year. The news is also a concern for banks. HSBC, Royal Bank of Scotland, Barclays, Lloyds Banking and Standard Chartered all feature prominently among the biggest fallers on Footsie.Elsewhere in the financial sector insurer Legal & General is friendless after Citigroup issued a sell note while London Stock Exchange (LSE) is still out of favour as analysts worry over how the Dubai debt situation will affect the 20.6% stake held in the company by Borse Dubai.On the plus side, Severn Trent and United Utilities move higher after water regulator Ofwat said the companies will have to cut bills in real terms between 2010 and 2015, though not by as much as it previously proposed. Ofwat said average annual bills will have to fall by £3 to £340 between 2010 and 2015, but this was less than originally indicated.FTSE 100 - RisersSevern Trent (SVT) 1,043.00p +3.68%United Utilities Group (UU.) 489.40p +1.09%Scottish & Southern Energy (SSE) 1,122.00p +0.45%Morrison (Wm) Supermarkets (MRW) 278.60p +0.14%Admiral Group (ADM) 1,054.00p -0.19%AstraZeneca (AZN) 2,771.00p -0.25%Marks & Spencer Group (MKS) 385.00p -0.28%GlaxoSmithKline (GSK) 1,285.50p -0.31%Vodafone Group (VOD) 138.35p -0.47%Cobham (COB) 229.40p -0.48%FTSE 100 - FallersRoyal Bank of Scotland Group (RBS) 33.48p -6.39%Legal & General Group (LGEN) 80.40p -5.13%London Stock Exchange Group (LSE) 778.00p -4.48%HSBC Holdings (HSBA) 708.20p -4.45%Xstrata (XTA) 1,052.00p -4.10%Kazakhmys (KAZ) 1,243.00p -4.09%Resolution (RSL) 83.00p -4.05%Standard Chartered (STAN) 1,542.00p -4.04%Aviva (AV.) 379.00p -4.03%Fresnillo (FRES) 865.50p -3.94%