Our new Secretary of State for International Development, Penny Mordaunt, has been in her new role for less than a month. But World AIDS Day provides an early opportunity for her to make her mark on what could be one of the greatest global achievements of the 21st Century – the ending of AIDS as public health threat.

The road has been long. Thirty years ago, the outbreak spun out of control and we lost too many lives through ignorance, stigma and slow medical progress. But the fightback has been strong too and the progress we have made means that people living with HIV on treatment have a normal life expectancy. In 2015, the global community confidently committed ourselves to the goal of ending AIDS by 2030 as part of the Sustainable Development Goals (SDGs).

The UK can be proud of the role it has played in getting us this far. But now the going gets really tough. For the first time in decades, progress is slowing and the risk of going backwards is intensifying. UNAIDS has warned of a $7billion funding shortfall and, this summer, the Bill & Melinda Gates Foundation highlighted figures showing that without this funding commitment, we could be facing a second coming of the epidemic.

So what is the UK Government doing about it? Well, unfortunately, the latest analysis of their political, financial, and programmatic commitments to the global HIV response backs up the sense that UK is walking away rather than stepping up.

In 2015, the UK’s strategy for tackling the global HIV & AIDS epidemic expired. There are currently no plans to renew it. The Department for International Development (DFID) has failed to send any senior political representatives to the International AIDS Conference for four years. In January, the International Development Committee launched an inquiry into DFID’s work on HIV & AIDS – they concluded that its political and programmatic commitment is insufficient.

Complacency is a killer. While focus shifts to new global health epidemics like the Ebola and Zika viruses, quietly AIDS is still one of the biggest causes of death for young people in the world. Over 100 adolescents die from AIDS related causes every day and it is the only demographic in which HIV infection rates is still increasing.

Thankfully, it is those very young people that are leading the fightback once again. This week I had the honour of listening to Davi, 26, from Indonesia, at the STOPAIDS World AIDS Day Parliamentary Reception. The sex-worker turned activist told his story of living with HIV and how he is supporting others to know and live with their status. Or Masedi, 22, who was born with HIV and is using her experience of growing up HIV positive as motivation to educate and empower young people to lead.

Then there is Youth Stop AIDS, the UK-based campaigning network who have been telling the world that It Ain’t Over for years now. They have encouraged hundreds of young people to write to their MP about the global epidemic and, today, they are engaging the public directly with 24 creative awareness raising stunts and events across the UK.

The It Ain’t Over campaign has three straightforward asks of the UK Government, which I support.

The first is about plugging rather than expanding that $7billion funding gap. We celebrate the UK Government for its recent and substantial commitment of an additional £1.1billion to the Global Fund to fight AIDS, TB and Malaria and for its continued status as the world’s second largest donor to the HIV & AIDS response. But our latest analysis of total DFID HIV funding indicates it dropped by 22% between 2012 and 2015.

The UK should reverse this trend and in particular invest in programmes that focus on the most vulnerable groups like sex workers, young people and men who have sex with men. The Robert Carr Network Fund specialises in this and is very successful. It is up for renewal next March and we want to see the UK increase its commitment to it.

The second is about prioritising young people. I’ve relayed some of the shocking statistics about how HIV & AIDS is disproportionately affecting young people, now it is time that DFID recognises it as a youth issue. That means putting the fine words of its Youth Agenda into action and ensuring that young people are supported as partners, leaders and advocates within the HIV response.

Finally, we need DFID to demonstrate proper, global political leadership. The UK has traditionally been viewed as a world leader in the HIV & AIDS response, but in recent years has relied on its financial commitment alone. Where there is not high level UK representation in international forums, less progressive states push through policies and strategies that harm our chances of making progress. For instance by marginalizing vulnerable communities like men who have sex with men, transgender people, people who use drugs and sex workers.

The UK is taking a step in the right direction by chairing the board of UNAIDS in 2018. It can also send the right message on its political leadership by ensuring there is senior ministerial attendance at next summer’s International AIDS Conference in Amsterdam. That would be a real statement of intent and supporting a youth advocate to join the British delegation too would help demonstrate that they are taking it seriously as a youth issue as well.

We know what we have to do. We have the tools and the knowledge to meet our target of ending AIDS as a global health threat by 2030. But only if countries like the UK step up their programmatic and political leadership now. So, Penny, my message to you is this: welcome to DFID and please don’t let the UK’s commitment to HIV drop because it ain’t over yet.