Rape and other forms of sexual violence in conflict are deliberate crimes against humanity, employed as a tactic of war and terrorism to systematically brutalise entire populations.

They are entirely preventable, which is why I launched the preventing sexual violence in conflict initiative (PSVI) in 2012 with UNHCR special envoy Angelina Jolie. From the start, we emphasised the crucial importance of addressing impunity. Without a realistic chance of justice being done, potential perpetrators of these crimes are unlikely to be deterred and the cycle of violence will continue.

We very deliberately invoked a high ideal – the eradication of the use of rape as a weapon of war. We did so understanding that this will take many years, and requires a major and permanent shift in culture and attitudes in many societies. While much can be done by establishing clear rules and providing the means to enforce them, the real victory will come when the great majority of people believe that crimes of sexual violence are fundamentally wrong and always to be prevented – in the home, the street, or the battlefield.

But in recent times no leading head of government or foreign secretary in the UK, or elsewhere, has been prepared to give this issue a high priority in their global work.

The Independent Commission for Aid Impact report into PSVI, published on Thursday, is timely and welcome. Icai has rightly called on the government to provide renewed senior leadership, reverse cuts in funding, and ensure that survivors’ voices are heard.

Eight years after the launch of PSVI, the possibility of progress has been clearly demonstrated. More than 150 countries have endorsed the declaration of commitment to end sexual violence in conflict. Suspects wanted for warzone rape can now be arrested in any of these countries. The first international protocol on the documentation and investigation of sexual violence in conflict has been used to document crimes and help survivors from Syria to Bangladesh, and was found by Icai to have been “widely-praised” and “instrumental in securing convictions”.

National action plans have been adopted by many of the worst affected countries; a UK team of experts has been deployed 90 times to respond to the urgent needs of survivors; and several leading national militaries have improved training and doctrine in line with the aims of PSVI.

No country can claim to be a leading force on human rights and development without taking up this gauntlet

Further progress has come in the form of legal reform in key nations, sometimes leading to prosecutions and compensation awards, as well as new funding for NGOs and the UN Trust Fund to End Violence Against Women, and a new global effort on tackling stigma among victims.

The 2014 global summit demonstrated that there is a vast global appetite to address these issues if efforts are focused and led.

From 2012 to 2014, clear championing of PSVI by the UK, at the most senior levels, showed that considerable momentum could be generated through persistent and senior advocacy by a prominent nation present in most global fora, allied to an imaginative campaign.

There are many obstacles to global action on such issues and, to many governments, our raising of the issue with them at the highest level seemed to come as a shock.

When I presented the case for action to the G8 foreign ministers in London in 2013, they initially reacted with surprise (in many cases) and obvious bemusement (on the part of some). An issue of this kind was not seen as part of a standard foreign policy discussion, but many of the ministers involved went on to become passionate supporters of the initiative, others became regional champions of the work, and every one of the 156 nations signing the declaration made formal commitments to which they should be held.

However, despite the valiant efforts of Lord Ahmad, there are clear signs of the usual global inertia returning.

There should be a systematic review of the commitments made by the countries and organisations that participated in the 2014 summit, involving NGOs and survivor organisations.

Where countries have fallen short of their previous commitments, there should be a diplomatic campaign to urge them to keep their promises, as well as to generate the political will needed to address current conflicts where sexual violence has been rampant.

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There is a compelling need for a permanent international investigatory body, capable of gathering evidence and preparing case files, to increase the prospects of more successful prosecutions. And governments should increase the proportion of their development budgets that they devote to programmes supporting survivors of sexual violence and other gender-based crimes.

The UK is still in a position to lead, and the fact that the government plans to hold a major conference this year presents an opportunity to intensify its work. But those efforts will only succeed if led at a very senior level within government. Precisely because this is such a huge issue, affecting the work of foreign ministries, defence departments, developments agencies and justice ministries, governments find it difficult to mobilise substantive action on it unless their very senior members are determined to do so.

If Boris Johnson’s government is ready to do this, it could have a powerful impact internationally. But if it is not, it would be better to let another country take the lead than leave the initiative underpowered.

No framework to preserve peace and protect civilians can be credible without addressing these crimes. No country can claim to be a leading force on human rights and development without taking up this gauntlet.