London open: Shares drop amid flood of results

London's blue chips are slightly lower as investors consider a mixed bag of corporate results on what is set to be one of the busiest days of the year.Cobham is leading the fallers, down more than 6%, after the defence and aerospace products group saw pre-tax profits fall in the half year to June 30 as it suffered from weakness in some of its commercial operations and delays in defence contracts.Banking giant Barclays is also down despite reporting a 44% rise in first half pre-tax profits as profits at the lender's investment banking arm, Barclays Capital, more than trebled, though that was partially offset by an increase in impairments in Barclays Corporate in Spain. Pre-tax profit rose to £3,947m in the first half of 2010 compared with £2,745m last time. Excluding movements on own credit, gains on acquisitions and gains on debt buy-backs, pre-tax profit increased by 22% to £2,963m.Randgold Resources posted a sharp rise in profits in the three months to June 30, despite lower production, on higher prices for the precious metal and upped its production target for a mine that is developing ahead of schedule.Insurer Aviva is currently the best performer after it reported a better-than-expected 21% rise in its half-year profit.Meanwhile, state-owned lender Royal Bank of Scotland (RBS) and insurance giant Aviva have confirmed that they are to renew their strategic partnership.RSA Insurance Group reported revenue growth in all geographic regions and a 'resilient underwriting result' in what was a tough first half for the insurance industry. Net written premiums in the first six months of 2010 rose 9% (6% at constant exchange rates) to £3.80bn from £3.49bn in the first half of 2009. Pre-tax profit was virtually flat at £302m.Fresh from its apparent success plugging the leaking Maconda well in the Gulf of Mexico with mud, oil giant BP has been given clearance to start the cementing part of its 'static kill' process.Mining giant Rio Tinto posted a record 125% jump in half year earnings and said it looks to the future with confidence. In a separate statement, the group said it received a binding offer from funds affiliated with Apollo Global Management and the Fonds Stratégique d'Investissement (FSI) to buy a 61% stake in Alcan Engineered Products (AEP), excluding the Cable Division. Hotel group Millennium & Copthorne saw profits soar in the second quarter as the sector - one of the worst hit during financial crisis - continued its recovery.Medical devices firm Smith & Nephew said it sees clear signs of progress in its US trauma and European businesses and a strong emerging market performance as it posted a 7% rise in second quarter trading profit.Capital Shopping Centres, the shopping centre arm of what used to be Liberty International, is enjoying the fruits of the property market recovery.Bookmaker Ladbrokes warned of a challenging consumer environment as it posted a fall in profits for the half year to June 30. Pre-tax profits fell to £105.1m from £130m on revenues that dropped to £500.2m from £565.1m. Housebuilder Bellway said it completed the sale of 4,595 homes in the year ended 31 July, an increase of almost 5%, at an average sales price of around £163,000 from £154,005 last time. FTSE 100 - RisersAviva (AV.) 376.90p +2.45%RSA Insurance Group (RSA) 131.60p +2.41%Schroders (SDR) 1,364.00p +1.94%Smith & Nephew (SN.) 570.50p +1.88%Schroders NV (SDRC) 1,120.00p +1.45%Man Group (EMG) 228.50p +1.15%ARM Holdings (ARM) 319.10p +1.14%Shire Plc (SHP) 1,444.00p +1.05%Lloyds Banking Group (LLOY) 75.10p +0.82%Rexam (REX) 309.90p +0.81%FTSE 100 - FallersCobham (COB) 223.90p -6.71%Barclays (BARC) 331.85p -2.35%Unilever (ULVR) 1,801.00p -1.64%Randgold Resources (RRS) 5,625.00p -1.57%Fresnillo (FRES) 1,082.00p -1.46%British Sky Broadcasting Group (BSY) 709.50p -0.91%Eurasian Natural Resources (ENRC) 955.50p -0.73%TUI Travel (TT.) 216.30p -0.73%Standard Chartered (STAN) 1,792.00p -0.67%Rolls-Royce Group (RR.) 571.00p -0.61%