London: An international protocol for dealing with rape and sexual violence in conflict was launched on Wednesday at a historic London summit on the issue, providing guidelines on the investigation of sex crimes and the collection of evidence for future prosecutions.

“For decades — if not centuries — there has been a near-total absence of justice for survivors of rape and sexual violence in conflict. We hope this protocol will be part of a new global effort to shatter this culture of impunity, helping survivors and deterring people from committing these crimes in the first place,” UK foreign secretary William Hague — who is co-hosting the summit with film star Angelina Jolie — wrote in a foreword to the 140-page protocol.

The Global Summit to End Sexual Violence in Conflict opened on Wednesday with 117 countries formally represented, plus scores of UN and aid agencies, civil society organisations, survivors, and nearly 2,000 delegates from around the world.

Zainab Bangura, the UN’s special representative on sexual violence in conflict, said conflict-related rape was no longer considered “a marginal issue, an inevitable by-product of war or mere collateral damage. It can no longer be amnestied or pardoned as the price of peace. It cannot be dismissed as a private matter. And the countless women, girls, men and boys affected can no longer be deemed second-class victims of a second-class crime.”

Bangura witnessed the enduring effects of sexual violence in the civil war of Sierra Leone. “The scars that remain beneath the surface of society make peace less possible. We’re here today to write the last chapter in the history of wartime rape and to close the book once and for all on humanity’s tolerance for such inhumanity.”

To survivors, she said, “your voices are being heard. Wartime rape is now among the greatest global security priorities of our time”. To perpetrators, “we will pursue with every means at our disposal. There will no hiding place and no safe haven. Sooner or later, we will get you This is not mission impossible.”

In a video message, Hillary Clinton paid tribute to Hague and Jolie as “formidable champions of this cause”. The summit was a historic opportunity to effect change, she added.

The protocol, funded by the UK government and the result of two years’ work, aims to provide best practice on the documentation of sexual violence. It includes practical advice, checklists and sample questions for fieldworkers.

For example, it provides a template for personal data to be collected from survivors and witnesses, tips on carrying out interviews and gathering testimonies, and guidance on photographing, filming and sketching crime scenes, and on the collection of physical evidence.

Around 25 experts were involved in compiling the protocol, whose contents were “field tested” in countries such as Uganda and the Democratic Republic of the Congo before publication.

Humanitarian agencies at the London summit have documented the long-term physical and psychological effects of sexual violence in conflict, including the rejection of victims by their communities and the birth of children conceived during rape.

Government troops and peacekeeping forces have not only failed to protect women from sexual violence, but have also been among the perpetrators, they say.

Jolie and Hague arrived together at the summit at the ExCel conference centre in Docklands, London on Wednesday morning. The pair were later due to co-host a screening of Jolie’s 2012 film about rape in Bosnia, In the Land of Blood and Honey, which led to the foreign secretary’s espousal of the issue.

However, criticism has been levelled at the UK government for failing to give protection to victims of sexual violence when they arrive as war refugees. Women were not being believed when recounting their experiences, and were being further traumatised by the asylum process, according to the Refugee Council.

“It’s critical that the government tackles this issue with the same gusto at home as it’s doing abroad and protects the survivors of sexual violence,” said Anna Musgrave of the Refugee Council, who said the UK government was guilty of hypocrisy.

At the opening session, UK foreign minister Baroness Warsi described “harrowing moments” as a lawyer hearing the testimonies of women from Bosnia-Herzegovina who were seeking asylum in the UK. “Having spent sometimes many, many hours with these women in preparing for their cases, we would find out only at the 11th hour the most horrific aspect of their experience — the rape and the sexual violence.

“And what was even more heartbreaking for me was when those women wouldn’t just tell you that at the last moment, but it would also be with a caveat — ‘But I don’t want you to tell anybody else this. I don’t want it to be part of my case’,” she said.

Angela Atim, who is speaking at the conference, was kidnapped at the age of 14 by the Lord’s Resistance Army in Uganda.

“These people who are accountable for the sexual violence in armed conflict, they have to be brought to justice,” she told the BBC. “It’s part of our healing because it’s really painful to see that they are still walking around, they are still doing the same thing.”