Being the Secretary of State at the Department for International Development is simultaneously the best and the most challenging role in Whitehall. It involves responsibility for a budget and department that are, at the same time, among the most transparent and the most scrutinised.

They will also make decisions every day that have the potential to have life-changing and life-saving impact around the world. And while they are likely to find themselves defending DFID from almost daily media attacks, this should not distract them from the department’s core work and the urgent need to tackle an unfortunately long list of global challenges.

From climate change to ending extreme poverty, to migration and responding to the increasing number of crises around the world, UK leadership is essential. Continuing to deliver the UK’s commitment to spend 0.7% of national income on aid and maintaining DFID as a stand-alone, cabinet-level department are two critical elements of that leadership, but it must go further.

The new Secretary of State should recognise that a coherent, whole-of-government approach is the only way to achieve an ambitious vision for the UK’s role in the world. Prioritisation will also be key – what are the areas where they believe the UK has comparative advantage and can achieve lasting change? They should identify these quickly and focus on them with relentless intent.

Leave no one behind is the hugely morally-compelling imperative to reach the poorest and most marginalised first with finance, programmes and policies. The UK played a leadership role in the development of the Sustainable Development Goals and, in particular, the commitment to leave no one behind.

But since then, other than excellent work on disaggregating data, DFID has dropped the ball on its high-level championing of this focus on ensuring that everyone makes progress.

So, what should the new Secretary of State do? First, they must cheerlead leave no one behind publicly. This will be easy. Next, they must walk that talk, ensuring at least 50% of aid goes to the poorest countries, and encouraging policy makers to spend it in the areas of greatest need within those countries.

Other steps will be tougher, but necessary. DFID will need to embrace a new appetite for risk and accept that prioritising the poorest and most vulnerable may be more expensive. Results frameworks will need to be more flexible. Surely the UK taxpayer would rather make sure aid reaches the people and places who need it most?

We’ve seen the impact of leaving people behind and marginalisation around the world. At a time when the UK is trying to build soft power for a global Britain, supporting countries to bring these populations into progress’s embrace – at the same time as tackling inequalities at home – will be vital.

Penny Mordaunt should put migration at the heart of her development policy agenda. It is clear that human mobility is an essential component of economic and social development everywhere and that migration can help achieve all the Sustainable Development Goals (SDGs), from poverty reduction, to health, education, climate change and citizenship. The new Secretary of State should ensure that this vision is at the heart of the Global Compact for Migration (GCM), to be agreed by the United Nations member states by September 2018.

DFID will soon be leading the GCM negotiations on behalf on the UK Government. First and foremost, the Secretary of State should insist that the GCM identifies and instigates concrete ways to better manage migration and facilitate human mobility; a failure to do so would miss the opportunity for change created by the so-called ‘migration crisis’ and its prominence on the global agenda.

Secondly, they should ensure that the Compact is grounded in the 2030 Agenda for Sustainable Development, committing to specific priorities where development policies can facilitate safe and orderly migration.

A good place to start is gender equality, where it is clear that migration offers unique opportunities for women to be lifted out of poverty, but can also expose vulnerable women migrants, and girls in particular, to abuse and exploitation.

Most importantly, the Secretary of State should ensure that aid is not used as, or justified as, a deterrence to irregular migration: the objectives of development are to reduce poverty and inequality, and foster growth. Migration can help achieve this, as part of a broader – and smarter – approach to the effective use of aid. 

As parties meet in Bonn at the UN Climate Change Conference, DFID must not be distracted from its responsibilities.

It is important that the Secretary of State recognises that the poorest are hit hardest and first by the impact of climate change. A delay in action to limit global warming to 1.5C will undo recent development progress – placing the greatest burden on those least responsible for creating the problem.

Rich and poor countries must coordinate their action, accepting the fact that climate change does not and will not respect national boundaries. Consequently, Mordaunt must scale up climate commitments ahead of 2020 – especially with respect to supporting countries to increase ambition within their Nationally Determined Contributions – and lead global negotiations to agree a Global Goal on Adaptation. The UK has both an opportunity and a responsibility to demonstrate global leadership.

Poor and vulnerable people need help building their resilience to climate shocks and adapting to climate impacts. Public investment in climate finance is needed to facilitate this and all financial flows must be compatible with decarbonisation. The UK Government must focus on these areas whilst leading efforts to phase out fossil fuel subsidies and supporting the pursuit of off-grid technologies so that everyone has sustainable access to electricity by 2030. The UK Government’s commitment to phase out coal-fired power by 2025 must be met. 

For 50 years, the UK has been at the forefront of upholding the values and principles that underpin humanitarian action globally. It is the third largest donor to emergencies and a country to which others look for policy leadership. At a time when 164 million people living in the midst of conflict have been driven from their homes or are struggling with the aftermath of disasters’ destructive effects, it is important that the UK government maintain its leadership role. 

The UK should prioritise crisis prevention, including acting early and substantially when there are signs of disaster or famine, and investing political capital and diplomatic energy in preventing conflict, and the violence and displacement that results. The UN Secretary General’s own initiatives on crisis prevention and sustaining peace will be important avenues for these actions.

When conflict occurs, the UK should continue to advocate for full compliance with International Humanitarian Law (IHL) by warring parties, and call for better monitoring of IHL compliance, including championing the appointment of a United Nations Special Representative to investigate violations. In cases of mass atrocities, it must use its position within the UN Security Council to call for the suspension of the Security Council veto.

The UK must also uphold its own commitments to critical international agreements in word and in deed, such as the Arms Trade Treaty and the 1951 Refugee Convention – and work with the banking and charities sectors in the UK to counter the impact of counter-terrorism measures that deter charities from operating effectively in humanitarian contexts and restrict remittances to conflict zones.

It will also be important for the new Secretary of State for International Development herself to continue to champion the benefits of a separate Department for International Development to advance and represent development and humanitarian principles at the highest levels of decision-making. This is a rare asset compared to other countries and underlines the UK’s commitment to humanitarian action.