The letter from 23 business leaders supporting the Tory position worked on several levels. First, it got the Tories’ tax cut back on the top of the news agenda along with its clear message: seven out of ten workers will be better off under the Conservatives. Second, it strengthened the Tory case that the risk to the economy is to increase the tax on jobs not cutting government waste. Finally, the problem for politicians in this anti-politics age is that voters aren’t inclined to believe what they say. But these business leaders who run companies people have heard of — Sainsburys, Mother Care, Marks and Spencer — are credible to the public and so their support will result in voters being more inclined to believe what the Tories say about National Insurance.