Michael Fallon is Secretary of State for Defence and MP for Sevenoaks.

It is four days since the horrific murder of Jo Cox. I will best remember Jo’s extremely informed and authoritative contribution to the debate over airstrikes in Syria, neatly summarised here: in the months since, she continued to press me on the plight of the Syrian people, trapped in that murderous civil war.

As we resume the campaign, let’s also remember how Jo approached politics – passionately, but with respect for those who disagreed with her. It’s in that spirit that I set out my position on the referendum.

I am a Eurosceptic.  I will vote to Remain.  And I believe that, as a Conservative, those two positions are not only consistent, but entirely complementary.

My conservatism means I am sceptical, even suspicious, of the EU’s centralising, controlling, coercing tendencies.  It has always seemed to me more like a process – towards ‘ever closer union’ – than an organisation.

But my conservatism also comprises a broader strand of scepticism.  Scepticism of radical change without proper consideration of the consequences.  Scepticism of turning everything upside down without a plan for what happens next.  Scepticism of risk, uncertainty and false hope.

I can understand what drives the desire to leave. I’ve experienced, both as MP and minister, the gradual encroachment of the European Court into our legal and political system. I get the frustration with the status quo and the appeal of a sunny future just out of sight.

But that doesn’t amount to a blueprint for guiding this country.  In their dreams of restoring ‘sovereignty’ or agreeing trade deals with our former colonies, what the Leave campaign really want is a different yesterday. What they lack is a coherent plan for tomorrow.

Indeed, many have asked: ‘would we join the EU if we were not already part of it?’.  But that is not the question. We are already part of the EU.  If we left, it would still be there, on our doorstep.  Conservatives have to deal with the world as it is, not the as we would like it to be.

My Conservative, Eurosceptic response, is: make it work for us.  That’s also the British way-  to fight, to lead, and not to run away when things get tough. A country of our standing can’t just stop the world and get off.  Instead, we should stay and work harder to shape Europe in our interests.  Those interests are the prosperity and the security of our people.

Our prosperity depends on our trade in goods, services and intellectual capital.  Almost half our exports go into a European single market bigger than the United States.  Our businesses have access to 500 million people with no tariffs or bureaucratic barriers.  And over three million jobs in Britain rely on it.  We have to be there to shape the rules that govern that trade.

Our security is similarly enhanced by our EU membership.

NATO is the cornerstone of that security.  As the Prime Minister’s renegotiation confirmed, Britain will never join an EU Army and we have a veto over all defence matters.  But the EU adds valuable tools that NATO cannot provide.  That’s why the current NATO Secretary General, five of his predecessors and four former NATO Supreme Allied Commanders want Britain to stay.  In fact, there isn’t a single NATO defence minister who wants us to leave.

It was the legal clout of the EU, not NATO, that helped bring Iran to the negotiating table, and delivered the first controls over its nuclear programme.

When Russia annexed Crimea, it was only through the EU that we were able to impose sanctions; NATO couldn’t do that.  And it is only through British leadership that the EU continues those sanctions today. Make no mistake – a vote to Leave would be payday for Putin.

Like it or not, the EU is now part of the collective security of the West.  If Britain – its largest defence spender – left, the EU would be smaller and weaker.  That would undoubtedly be welcomed by Britain’s enemies around the world.  No ally, no partner, no Commonwealth country wants us to leave.

As Defence Secretary, I know that the global challenges we face cannot be confronted without cooperation between NATO and the EU, with Britain at the heart of both.

That doesn’t mean an EU army. I want to be absolutely clear on this, because what the Leave campaign is saying is wrong. We retain a veto on all defence matters in the EU, and we would oppose any measures that resembled the creation of one.

Make your own decision on how you vote by all means. But don’t base it on fears of an EU army that we will always block and would never be part of.  And, by the way, does anybody seriously believe France would allow its troops to be merged into a European army?

So those who want to Leave owe it to the British people to explain how they would guarantee our security and prosperity outside the EU.

Yet all we have had are vague promises and carefree assurances that everything would carry on as normal – that Britain would get everything it wanted from the EU, without having to make any of the compromises associated with EU membership.  For a sceptical Conservative, that isn’t credible.

All that is certain about a vote to Leave is the uncertainty that would come with it.  Uncertainty for sterling, for our access to the biggest free-trade single market in the world, and for our financial services industry, which relies on the ‘passport’ of EU membership to sell across the continent.

The Conservative Party has already shown how Europe can be better shaped in the British national interest.  We secured a big budget rebate.  Margaret Thatcher changed an agricultural union into a real common market in goods and services.  John Major broke the EU’s monopolistic mindset, enabling Britain to keep both our currency and our border controls.  If we Remain, we can retain these advantages and build on them the changes secured in David Cameron’s renegotiation.  And with renewed British leadership, the process of reform can go on.

So that is how we must approach this choice: neither as fanatics for more integration nor as victims of an inevitable process, but as Eurosceptic Conservatives, ready to do the harder thing: the unglamorous, painstaking championing of our interest from within.

I know the EU is often frustrating.  I know it is not just the common market we signed up to anymore.  But if you leave, you have to be going somewhere.  When we wake up on the morning of Friday 24th, Europe will still be there, just 20 miles across the Channel.

Vision, zeal, ambition for our country – yes, these are important parts of the Conservative tradition.  But in delivering them, conservatism is also the art of the practical and the possible.  For our security and our prosperity, we have to make Europe work.