Concerns in Davos about Cameron's EU referendum pledge

David Cameron vowed to hold a referendum on the UK's membership of the EU by the end of 2017. Photo: PA Wire

Sir Martin Sorrell is often described as the "ultimate Davos Man". The chief executive of advertising company WPP has been coming to the World Economic Forum for many years and is never shy of media interviews to spread his message. This morning Sir Martin's people called ITV News' people to see whether our interview with him could be moved from 0700 to 0645 - Davos Man is an early riser.

Sir Martin is worried about the Prime Minister's pledge to put Britain's membership of the European Union to a referendum. Like many of the business people I've spoken to here, he agrees that there are many aspects of the EU which could be improved (he advocates bendy bananas) but the in/out question is troubling him, particularly the fact it won't come before the next parliament. "Who puts off a decision for four years," he asks, raising his eyes heavenward. "This is a political step, certainly not a financial one."

Sir Martin Sorrell, chief executive of advertising company WPP. Credit: PA Wire

Mr Cameron is speaking at the Forum later this morning and will face a lot of quizzing. I haven't spoken to anyone here (or spoken to anyone who's spoken to anyone) who welcomes his plans. Perhaps that's because most business people here are internationalist: they're the big, global companies for whom trade really matters (although 55 business leaders in the UK, including the bosses of exporters like Diageo and Rolls Royce, have written to the Times this morning, lending their support to the Prime Minister).

The uncertainty (and that's definitely the word of this year's British Davos participants) which the delay in a referendum creates will put off investment: a South Korean company that wants to build a factory in Europe, for example, may just wait until matters become clear or build it in Ireland instead of Britain. When our own economy is struggling to spark into life, decisions like that would be a bitter blow.

What's exercising Sit Martin most, however, is that a referendum due by the middle of the next parliament will be badly timed. "The irony in all this," he says, "is that I reckon that's precisely the time when continental Europe will be turning the corner. That cyclical upturn will come and if we go out [of the EU], that's not good."

FOMO (Fear Of Missing Out) may be a theme of Davos yet to come.