FTSE 250-listed financial services company Legal & General has put in place a longevity insurance arrangement for defence and aerospace company BAE Systems' 2000 Pension Plan.The deal is the largest such arrangement ever completed in the UK.The arrangement insures the plan against the financial risk of its 31,000 current pensioners living longer than expected, covering a total of £2.7bn of liabilities as measured by the plan, or £3.2bn discounted at LIBOR. Legal & General will retain 30% of the longevity risk, with the remainder being reinsured by Hannover Re.Nigel Tinsley, Group Pensions Director at BAE Systems, said: "We are pleased to have worked with Legal & General and Aon Hewitt to develop this innovative approach to managing risk exposure within the BAE Systems 2000 Pension Plan. "This arrangement offers us a flexible approach to managing the key risk of longevity in the plan. We are particularly pleased that we were able to complete the process in a structured and straightforward fashion within six months."Legal & General's share price contracted 0.89% to 155.20p at 09:55 on Thursday.MF