Leading lights from UK business have come out in support of Conservative plans to halt Labour's planned rise in National Insurance (NI).Bosses of large UK companies, including Justin King, chief executive of the supermarket operator J Sainsbury and Mick Davis chief executive of the mining giant Xstrata, wrote to the Daily Telegraph saying: 'The Government's proposal to increase national insurance, placing an additional tax on jobs, comes at exactly the wrong time in the economic cycle.'They welcomed shadow chancellor George Osborne's plan to block the proposed rise. Osborne says he has identified £12bn of savings that government departments could make and that these will be used to block NI rises for people earning less than £45,400 a year.The letter was signed by 23 business leaders. Other signatories included fashion chain Next chief executive Simon Wolfson, a prominent supporter of the Conservative Party, Paul Walsh, boss of the drinks firm Diageo and Marks & Spencer chairman Sir Stuart Rose.'In the last two years, businesses across the country have cut their costs without undermining the service they provide to their customers,' they said. 'It is time for the Government to do the same.'