The voice of business has been all but silent in the Brexit debate ever since former Marks & Spencer boss Stuart Rose made such a hash of trying to lead the pre-referendum ‘Britain Stronger in Europe campaign’. Now suddenly there’s a business cacophony: Airbus, BMW, Siemens and the heads of the CBI, the Institute of Directors, the Federation of Small Businesses, the British Chambers of Commerce and the Engineering Employers’ Federation, all saying roughly the same thing: never mind the politics, all we ever asked for is clarity, preferably accompanied by ‘frictionless trade’.