Mills, a Labour-party supporter and long-term supporter of a "Brexit" (the campaign to leave the EU), told CNBC that there were a "number of concrete issues" that should determine how voters vote in the referendum on EU membership on June 23.
"The European Union is a very expensive club for us to be in; in 2014 it cost £11.4 billion ($16.4 billion) which is a very large sum of money. There are obviously problems about border control and very large numbers of people coming in from Eastern Europe to the U.K….there are problems around democracy and control and there are structural problems.
Mills' comments come as the debate heats up over whether the U.K. should stay within or leave the European Union and polls suggest a tight race between the "leave" or "stay" vote.
Some financial institutions want to distance themselves from the so-called "Brexit" debate. Bank of America has reportedly advised its staff not to use the word "Brexit" with clients, according to the Financial Times newspaper. The bank has told its managers to "avoid engaging in the campaign." This comes after the bank also reportedly decided against giving a £100,000 donation to the pro-Europe camp.
Meanwhile, the bosses of several British companies including JD Wetherspoon and the former boss of HSBC have pledged their support for the "Brexit" campaign. The chief executives of Rio Tinto, Ryanair, Shell and Unilever have argued that it's in the best interest of the U.K. economy to stay within the EU.
Mills said that the "business world is very split on the issue" and this division would continue up to the vote.
"By and large, the big companies that tend to benefit from the scale of the European project and their ability to lobby in Brussels…tend to be in
favor of staying in but the more entrepreneurial companies tend to be less enthusiastic. I think this split is going to continue right up to the referendum."
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