The Bank of England (BoE) Governor Mark Carney said on Thursday that the U.K. should hold a referendum on membership of the European Union (EU) "as soon as necessary".
Analysts fear that businesses may delay making investments due to the uncertainty over UK's future in the EU.
Carney noted that there is no evidence yet businesses have acted on the uncertainty.
The BoE governor pointed out that Europe is important to the UK's economy.
The Conservatives have promised to hold a referendum before the end of 2017. The government in the U.K. hopes that a referendum could be held in 2016.