James Cleverly is MP for Braintree.

Britain is booming. British people and British businesses should be proud of what they have achieved in recent years, particularly in comparison to the slow and ponderous Eurozone. While the UK has confronted and overcome the difficulties of the last decade, the EU has shown that is too inflexible to successfully handle the challenges and opportunities of the 21st Century.

We have cut unemployment because of our flexible job market and the Chancellor’s decisions on welfare and the economy, while in Europe unemployment is rampant. We instinctively look towards new and growing markets for trade and inward investment, while the EU is becoming increasingly defensive and introspective. We understand that cutting regulation and taxes frees people and businesses to prosper, while the EU still churns out miles of red tape and taxes until the pips squeak. The last few years have convinced me that Britain would be better able to grow, trade with emerging markets, flourish and prosper if it were outside the EU.

I have not dismissed the renegotiation out of hand; I have supported the Prime Minister’s efforts to secure a new deal from the EU and I still hope he can persuade other heads of government to embrace meaningful change. It has, however, become increasingly clear that despite the Greek crisis, the refugee crisis, border control chaos and economic stagnation, the EU still doesn’t see the need for fundamental reform.

I want the Prime Minister to get the very best deal possible from these renegotiations. This referendum is too close to call and if the UK votes to remain in the EU I want it to be on the best terms available. If we vote to leave then the deal will form the basis for our post-membership relationship. Either way it is better if David Cameron gets a good deal.

If our EU partners don’t believe that there are any circumstances under which we’d leave, why would they make any meaningful concessions? When big beasts say that the EU is deeply flawed in many ways and unwilling to change but that we should nevertheless stay in, it weakens the Prime Minister’s hand.

I have made my position clear now, ahead of the February renegotiation meeting, in the hope that EU leaders realise that they still need to give ground to win over the UK. It may feel like a stone in his shoe and it will be reported as disloyal but it is massively to the Prime Minister’s benefit for there to be a credible and active Vote Leave campaign.

Over the course of the campaign all Conservatives should remember that there would be no renegotiation without the referendum, no referendum without a Conservative victory, and no Conservative victory without David Cameron. Those expecting, or hoping, that I will slate the Prime Minister over the EU will be left disappointed. I don’t see anyone else who would have done a better job in these talks but I fear the people he is negotiating with just don’t get it.

I wrote a post for this site last year saying that Conservatives should conduct this referendum campaign in a way that doesn’t undermine our ability to work together afterwards. I stand by every word of that. I will be campaigning for an issue I feel strongly about, not campaigning against colleagues who disagree with my position. Some of my closest political friends will probably campaign to remain and I have no intention of losing them as friends over this issue.

Not only is there a chance for us to show that a referendum campaign can be conducted professionally, but Conservatives should be seen heading up both sides of this debate. This will be one of the highest profile activities of 2016 and if we don’t also front both camps then another political party will. Neither Labour nor UKIP deserve the media boost that heading the Leave campaign will give.

The case for a new relationship with European and global economies is overwhelming. The EU too often hinders Britain’s ability to trade across the globe and pursues discriminatory policies that hold back developing nations. We need new relationships and, without that fundamental change in the EU, the only way that will be possible is for the UK to leave.