David Cameron will urge business leaders on Thursday to speak out and help him keep Britain in the EU, as he attempts to launch his referendum campaign with a barrage of corporate support.
Mr Cameron, speaking at the World Economic Forum in Davos, will urge business leaders to overcome their fears of entering the political domain, declaring: "This is a once-in-a-generation moment and the stakes are high."
The prime minister is acutely aware that business leaders only belatedly entered the Scottish referendum debate in 2014, but argues that their voice was influential when it was finally heard.
Mr Cameron's aides and pro-EU campaigners have been holding private talks with business chiefs to urge them to speak out early in the referendum campaign, which is expected to start next month.
"The voice of business must be heard in Britain and across the whole continent," Mr Cameron will tell an audience of global business and financial chiefs at the Swiss resort.
"If you want a more competitive Europe, where the single market is completed, where there are more trade deals and fewer regulations: join me in making that case.
"If you believe, like I do, that Britain is better off in a reformed European Union, then, when the time comes, help me make that case for Britain to stay."