Amlin swung to a deep loss in the six months ended 30 June, as a result of what the FTSE 250 insurance and reinsurance underwriter called "unprecedented first half catastrophe loss activity".The firm reported a pre-tax loss of £192.3m in the period, down from a profit of £107.6m in the same period the year before. Loss per share was 30.7p, compared with earnings of 17.1p per share previously."Exceptional catastrophe losses in the first half of 2011 have taken a heavy toll on the reinsurance industry, and Amlin has been no exception," said chief executive Charles Phillipps.The combination of the Queensland floods, the New Zealand and Japanese earthquake, and the tornadoes in the US resulted in Amlin's claims ratio (or loss ratio: claims divided by earned premiums) surging to 92%, up from 63% the year before.Nevertheless, the group said that reinsurance rates have subsequently improved, with gross written premiums reaching £1.51bn, 1.9% higher than the £1.49bn seen the year before.The interim dividend was maintained at 7.2p."While our results are disappointing, the core underwriting businesses in London and Bermuda are well placed to take advantage of an improving rating environment, particularly in catastrophe lines. We remain focused on addressing areas of underperformance and I am confident that Amlin can continue to deliver excellent long term returns for our shareholders," Phillipps said.BC