London's top stocks have opened sharply lower as investors consider this morning's news that the UK is heading for a hung parliament.Latest projections are for the Tories to be largest party but will fall short of majority, as David Cameron's party fails to take many key target seats while Labour is pushing to form coalition with Lib Dems. The latest polls suggest the Tories will end up with 307 seats, Labour on 261 and the Lib Dems on 54. Part-nationalised lender Royal Bank of Scotland moved into profit at the operating level during the first quarter of 2010 as impairment charges fell, although there was still a small pre-tax loss. Operating profit for the three months to 31 March was £713m compared with a £1.35bn loss a year ago, but the bank lost £21m before tax. ITV warned that the market outlook for the second half highly uncertain as it reported a 6% rise in revenues. The broadcaster's revenues in the first half increased to £450m compared with £425m last time. Broadcasting and online revenues were also up 6% to £390m, while ITV Studios external revenues rose 7% to £60m (2009: £56m), with internal production revenues at £73m (2009: £75m).BP says its 'coffer dam' has arrived at the site of the leak in the Gulf of Mexico and should be in place within two days as it attempts to stem the flow of oil from the crippled Deepwater Horizon rig. It may also need some sort of wall to protect it from the wave of writs heading its way for the tragedy. The Times reports that up to 200 American lawyers are planning a class action representing hundreds of individuals and businesses affected by the Gulf of Mexico spill.Underwriter Chaucer has estimated its net losses from the Deepwater Horizon rig disaster in the Gulf of Mexico at $25m. Rival underwriter Catlin estimated its exposure to Deepwater Horizon-related claims in second quarter at $40m net of reinsurance and reinstatements.Flight cancellations following last month's volcanic ash cloud from Iceland left passenger numbers at easyJet down 7.6% on April 2009 and 800,000 less than expected. The low-cost airline sold 3.49m tickets in April, down from 3.78m a year earlier, but the company had expected to fly 4.3m passengers, which would have represented growth of 14%.