Christian Guy is the former Director of the Centre for Social Justice, and a former Downing Street advisor.

It was three years ago in one of Brazil’s favelas that I first encountered the scale of the development challenge, and the importance of British engagement. Fatherless families in leaking tin shacks – five children to a mattress – with damp and disease all around. Piles of rotting garbage and flowing sewage provided a playground for toddlers in nappies. Flooding from the fast and filthy river was a way of life. Stray animals were roaming and adults languishing in a lawless neighbourhood. This was as close to hell on earth as I had seen – and this was supposedly a country on the rise.

Just one small community, in one large country, on one enormous continent. And it struck me, there in the middle of that slum, that the complexities of aid spending originate from the complexities of the problems it tries to solve. Despite Brazil’s sizeable economy and relative wealth, it felt as though the entire DfID budget could be directed to this dark corner of South America and still fall short. Further still I thought, what of the poorest in failed and fragile states which lack the hope found in Brazil’s ongoing economic transformation?

Britain and our challenges suddenly seemed smaller, and eminently solvable in comparison. But the little girls we met there and see around the world are no less important and no less full of potential than mine. The parents raising their children no less deserving of healthcare, safety and opportunity.

The British people have a deep and long-held a commitment to helping the very poorest, and want to see these countries supported to turn themselves around. We need to protect this with everything we’ve got.

Cautious optimism but no complacency

It is too early to judge, but Theresa May seems to share this commitment. Minutes after becoming Prime Minister, she made two pledges that I hope will come to define her time in Downing Street: to fight what she described as “burning injustice”, and to reshape Britain’s role in the world successfully following the EU referendum.

One thing about that is abundantly clear: for a nation as strong as ours, and in today’s globalised world, these challenges are deeply intertwined. Fighting injustice cannot stop at Britain’s borders, and our “bold, positive new role” post-Brexit must be one that promotes opportunity here and overseas.

Part of that must be built on a determined recommitment to effective international development – championed passionately by the three Prime Ministers who preceded her.

Yet, looking ahead, those of us who consider this integral to our national interest and the prospects of our fellow citizens around the world must face facts: our commitment to overseas development may not survive the renewed political pressure it is coming under post-Brexit unless greater public support is secured and our critics taken on.

For many who campaigned against it, Brexit threatens a new era of isolationism and insularity. Remainers worry that ‘taking back control’ actually means checking out of global institutions and washing our hands of major problems – the mass movement of the displaced millions or human rights being two prominent examples. Those who won the referendum though argued that leaving the EU would allow the UK to be more outspoken, a more significant global influence and provide true freedom to lead on the most important issues facing the international community.

Time will tell, but there is some cause for optimism under this Prime Minister. Working with me and my team at the Centre for Social Justice when she was Home Secretary, I was inspired to see her lead the world in the fight against modern slavery, overcoming initial Westminster indifference, Whitehall apathy and scepticism from powerful vested interests. Introducing child-trafficking advocates and an independent Anti-Slavery Commissioner, as well as creating tough new powers to tackle traffickers and increase transparency in big business supply chains, the Modern Slavery Act was one of the most significant achievements secured by the last Government. She and David Cameron were rightly proud of that legislation. It broke the mould.

Other governments were inspired, too, by what was possible for the most disadvantaged and exploited people across the world when Britain led the way. And this is the spirit the May Government must now channel to meet the twin challenges the Prime Minister outlined on the steps of 10 Downing Street. A commitment to social justice – effective poverty-fighting and development – must be at the heart of this country’s new global role.

Improving public understanding of aid

The political context, and a damaging lack of confidence in our aid spending in certain sections of the public, means it is vital our new Government – and the sector – gets to work bringing the British public onboard in new ways. International development has too long been seen as a soft target by many in the press, particularly on the Right, and as wasteful and unnecessary by its increasingly vocal critics. So the case for action and the way we work must be considered afresh.

That begins by being hard-nosed in our scrutiny of aid spending, cutting out waste and tackling corruption head on. This will breed greater confidence. We know David Cameron’s Government was ranked as the world’s most transparent by the World Wide Web Foundation in 2015, and Theresa May should build on this achievement. The Department for International Development has led the way in terms of aid transparency, not only through Andrew Mitchell’s foundation of the Independent Commission for Aid Impact (ICAI), but also with advances such as the DevTracker website, which details and maps every project funded by British aid. They should find ways of selling these reforms more widely and connecting real people to the results.

This kind of innovation can’t end here though, DevTracker is a great example of the conundrum of Government transparency – it is a data overload, with little public appeal. There are many examples though of how data can be much better harnessed to improve its impact. Professor Hans Rosling’s Gapminder Foundation describes its work as “fighting devastating ignorance with a fact-based worldview that everyone can understand”; they present a treasure trove of data on every aspect of global development in a customisable online portal. Similarly, the Centre for Global Development’s Aid Quality Index gives an interactive ranking of countries and agencies which give aid, based on their work in different sectors. These are tools that are simple and easy to use, and allow users to digest and engage with the data. While I’m under no illusions that an equivalent from the UK’s Department for International Development would become wildly popular, it is this kind of innovation that is required to shift the narrative around the way British aid is spent.

More easily accessible data about British aid also allows us to highlight its impact, and research by Save the Children and Conservative Friends of International Development (CFID) suggests that this is the most powerful way of engendering support. While the research finds that there is a basic desire amongst voters for Britain to help the world’s poorest and most vulnerable, this is muddied by very low levels of understanding about how taxpayers’ money is actually spent on international development, which leads to assumptions of corruption. So the fact that support increases when the low base-level of knowledge about aid is increased is an encouraging sign, and proves the importance of better communicating its impact. The raw support for British aid exists, but it is damaged by a lack of knowledge.

This reflects a much broader truth that presenting people with the evidence of results is much more effective than discussing their ingredients. We speak about aid too often in terms of billions of pounds or a proportion of gross national income (GNI), and too rarely in terms of its achievements. But consider this: since 2011 the UK Government has responded to 32 humanitarian crises, given 11 million children a chance in life by supporting them through school, and improved nutrition for over 30 million children under five. This is the clearer language we must adopt.

Making aid personal

Of course the International Development Act, and its commitment to the 0.7 per cent aid target, divides opinion – particularly on the right. But if we are to build public pride in development and the children’s lives we save in the darkest corners of the world, let’s not restrict the conversation to percentages. Instead, for example, we should talk about the 1,600 NHS staff and 800 UK military personnel, along with hundreds of British charity workers, who deployed to West Africa to combat the Ebola virus and prevent it spreading further. They trained 4,000 local staff, delivered 1,800 tonnes of supplies, ran three labs, built six treatment centres, saved countless lives and helped to stop the spread of the disease – helping to end the epidemic and leaving the region more ready to stand up for itself next time. This is what Britain can do when we lead, and we must celebrate it.

Bringing public opinion more squarely behind Britain’s aid budget is not just a communications exercise though – it requires us to rethink many of the things we take for granted. We have to find ways to democratise development here. The ‘Send My Friend to School’ campaign is a great example of this – it allows British school children to reflect on their own education, and use it to press the importance of what is now a global UN goal – a commitment to provide education for all under-16s by 2030. This is a good example of how engaging members of the public with causes that they can relate to is done effectively by NGOs, and could be adapted by Government to increase support for aid.
Similarly, the Water Project provides donors with the GPS coordinates of wells that they have helped to fund, and organisations like Plan International help individual donors to sponsor individual children. While this direct link is often to some extent artificial, it is an approach that could inspire DFID to better connect their spending to the public who fund it. There is no doubting the compassion of the British public, not only from the evidence in Save the Children and CFID’s research, but from their generosity to charities, and at events like Comic Relief which seem to break fundraising records every year, but more can be done to harness this generosity in support of the aid budget.

Increasing our appetite for risk and innovation

As steps are taken to improve value for spend, we also have to be honest with the British people and across party lines about the fact not every pound can be transformative. It is difficult work in theatre, and we have to face the critics about this head-on. Just as we recognise the importance of some flexibility in investment when it comes to domestic policy – such as piloting new programmes or innovation in medical treatment – so too the challenge with development spending comes in designing evidence-driven interventions, delivering them efficiently in the toughest places on earth and rooting out those that are less effective.

Sometimes critics seem to forget that British aid takes us to the most volatile nations, and requires engagement with radically different systems. These are places where, by definition, market forces have failed to provide prosperity and problems are entrenched. So a ruthless intolerance of waste must not end up being an innovation blocker. Accepting that some interventions will need refinement and others may be abandoned should not call into question whether DFID’s work is right in principle. Those who seek to score points on the back of this fine balance play politics with people’s lives and undermine our role in the world. We have to forge a fresh consensus in politics – across left and right – which takes them on.

The Prime Minister has an ambitious vision for her Government, and arguably, despite near total political dominance, she has a harder course to navigate than any of her recent predecessors. Most details remain undefined, but her pledge to forge a new role for Britain on the world stage presents an exciting opportunity to improve the way we act for the world’s poorest people.

If, supported by the sector, she seizes this moment to tackle injustice, then Britain can again lead the global movement for sustainable development. But together we have to build new public engagement and trust, and harness the latent public will to help those less fortunate as we do so. This means making the case for aid with confidence, being meticulous with our spending and finding new ways to bring the British people into the effort as we save lives and rebuild countries. There can be no wider or more meaningful an impact for a Prime Minister than that.

This is the second of three essays from Our Today, Their Tomorrow, published by Save the Children, which will run on ConservativeHome this week.