For a thoroughly modern politician, David Cameron appears to have some strangely antiquated ideas about how the modern global economy works. This week, the Prime Minister will board a plane to India in the company of scores of senior British businessmen. At the other end, much flesh will be pressed and the merits of British firms loudly trumpeted. A new defence contract for BAE Systems is expected to be brandished. This is the traditional way of conducting trade policy. It is also thoroughly outdated. If there is business to be done between Britain and India, the private sectors of each country are perfectly capable of getting on and doing it without politicians of either nation smoothing the way.