Business leaders and economists at the World Economic Forum in Davos have been divided over David Cameron's referendum plans.
Among the criticisms is the potential timing of the vote, with Britain possibly deciding on whether to stay in the EU just as its members are coming out of recession.
From Davos, ITV News Economics Editor Richard Edgar reports:
To the surprise of many Lib Dems, Nick Clegg appears to have played down the importance of the Coalition's divide on an in-out referendum.
Business leaders in Davos are worried about the Prime Minister's pledge to put Britain's membership of the European Union to a referendum.
With some in France keen to "roll out the red carpet" for a British exit, Germans favouring decentralisation welcome EU renegotiation talks.