05/07/2016 03:55 BST | Updated 05/07/2017 06:12 BST

Brexit Britain Needs a Socially Mobile Britain More Than Ever Before - That's Why I'm Backing Theresa May

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In the fortnight following the EU referendum result, minds have been focused on our approach to Brexit and how we make a success of Britain's new path outside the EU, on when to trigger Article 50 and what kind of renegotiated deal is best for Britain. But it is easy to miss that a huge part of Britain's future success is something that is - and always has been - directly within our own gift: how we drive opportunity and social mobility in our country, and unlock the energy and talent of millions of our citizens.

These are issues that have shaped my own personal and political life, the link between effort and reward, having a politics that works with the grain of human nature and not against it: they are why I am a Conservative. It's also why I want to see Theresa May succeed David Cameron as leader of the Conservative Party and Prime Minister. No other candidate offers both the commitment to make Britain a country that works for everyone - regardless of who they are and regardless of where they are from - with Theresa's formidable track record and experience serving the nation in government as Home Secretary.

Making Britain a place that enables our young people to become the very best versions of themselves they can be isn't just about their success, it's about how we make sure we are successful as a nation. A big part of how we unite our country after the EU referendum must be an even stronger focus on opportunity. It's got to be a level playing field of opportunity for everyone - that's how we will deliver the country that Theresa May describes, one that works for everyone, not just the privileged few.

And doing that the Conservative way means levelling up opportunity for those who don't have it, not taking it away from those that do. For me as a young girl growing up in Rotherham in the 1980s, including a year when my father was unemployed after being made redundant by British Steel, I knew that other children were in places that were doing better, with more jobs, but I never believed that the solution to my and my family's situation would be to take opportunity away from those that already had it. Then everyone would have lost out. Far better and smarter to level up, to go to the places with poorer education, weaker job and careers opportunities and fix that at source. That's what I needed then, and for young people growing up in today's social mobility 'cold spots', that's what they need now.

Unleashing social mobility means liberating the opportunity givers and the opportunity takers. It means changing all of our attitudes as to how far we can go and what we can achieve, and lifting our sights upwards, understanding we can all play a role in helping the next generation up the ladder. Our education system needs to produce young people who are aiming high and then our business world needs to harness and nurture that talent. As a government we've already done a huge amount, lifting the cap on university student numbers and creating apprenticeships, all underpinning the opportunities that flow from having a strong economy. But there's much more to be done.

As Theresa has already made clear, the mission to make Britain a country that works for everyone means having a Conservative Party that works for everybody. Theresa was one of the first people to recognise that the Conservative Party needed to modernise - and then act on it, for instance opening up the Party and giving better opportunities to women to progress and run for election. As Home Secretary she has taken on some of the most serious and difficult challenges that a nation can face, getting on with the job, and achieving results in the national interest.

Driving opportunity and social mobility has to be at the centre of government for the rest of this Parliament and far beyond, and we also need a strong leader who has the clout and experience to get the best deal for Britain and put us on the best possible path post-Brexit. Theresa May can provide that leadership, and that is why I am supporting her.

Justine Greening is the Secretary of State for International Development and Conservative MP for Putney