The G8 group of leading countries has pledged to end sexual violence and rape in conflict in an historic announcement.
William Hague confirmed the agreement at a meeting of the G8 foreign ministers at Lancaster House in London.
He was joined by the actress Angelina Jolie who is a Special Envoy for the UN Human Rights Council, and Zainab Bangura, the Special Representative for the UN on sexual violence in conflict.
Mr Hague likened the crimes to the slave trade, saying rape in war zones is "one of the greatest and most persistent injustices in the world".
He added: "It is almost one of the most neglected."
The agreement will result in money pledged to fight the crimes.
Britain is providing £10m from the budgets of the Foreign Office and Department for International Development.
The pledge will make up part of the £23m package pledged by the G8 nations at the London meeting.
The G8 has also agreed that there should be no amnesty for sexual violence in peace agreements, and committed to developing an international protocol to investigate such crimes.
Soldiers, who are sometimes the first to come across victims in conflict zones, will receive dedicated training to deal with such scenarios.
Mr Hague and Jolie have worked together on the agreement over the past year.
Last month they travelled together to the Democratic Republic of Congo , a country with one of the worst records of rape as a weapon on conflict.
Speaking alongside Mr Hague in London, Jolie said: "International political will has been sorely lacking. But today I believe that their (the victims') voices have been heard, and that we finally have some hope to offer them."
Britain has pushed the issue as part of its presidency of the G8 and the Foreign Secretary has said he intends to take it further when the UK assumes Presidency of the UN Security Council in June.
International Development Secretary Justine Greening said: "Britain will not stand on the sidelines while so many are denied the chance to reach their full potential and live safe, happy lives.
"We know that girls and women are at their most vulnerable at times of conflict or humanitarian disaster but we need to know what works best to tackle the terrible, often sexual, violence they face."