Businesses are showing that they are shifting away from voting in favour of the UK remaining in the EU. According to Deloitte's CFO survey, only 62% of finance chiefs are against a Brexit, down from 74% in the second quarter of 2015.

Although a significant majority still prefers the option to leave the EU, UK companies are becoming more aware of the effects the organisation has on business in Britain.

"A clear majority of CFOs continue to favour of the UK remaining in the EU, but the proportion of those expressing unqualified support has fallen," stated David Sproul, Deloitte CEO, in the report. "This mirrors what we have seen from the broader public in opinion polls in the last six months."

Big names in the City, such as Virgin tycoon Richard Branson and easyJet CEO Carolyn McCall, have joined Britain Stronger In Europe, headed by former M&S boss Stuart Rose.

Lobby groups both in favour and against a Brexit have started gearing up ahead of the referendum. On the other side of the debate are Ukip-backed Leave.EU and CBI hecklers Vote Leave.

"Although CFOs are negative about prospects for the euro area, activity in the region picked up through 2015, and at a rather faster rate than expected," the Deloitte report read. "German business confidence ended 2015 at higher levels than at the beginning of the year. Meanwhile US manufacturing activity dropped to a six-and-a-half year low in November."

Although many business lobby groups have come out in support of the UK remaining in the EU, there is a clear split in the City. Those anti-Brexit see the advantages of a huge consumer market and export perks with a market that represents the majority of UK trade, while others say the bureaucracy and strict regulation is limiting the potential of British businesses.

The sluggish recovery and dangers in the Eurozone economy are also concerns for businesses. These elements have even dented business confidence in the UK.

However, voting to leave the EU will have significant risks for the wider UK economy, according to Societe Generale. The French banking giant claimed that a Brexit would lead to slower economic growth for at least the next decade, while the pound would slip in value.

"There is a high risk that the UK could vote to leave the European Union with significant economic damages resulting from such a risk scenario," said head of global research Patrick Legland.