During my years in Bosnia, both during the war and afterwards I heard and saw evidence of horrific stories of mass rape and sexual violence committed during the war. Thousands of women and children suffered terrible abuse and the physical and mental scars could stay with survivors for the rest of their lives.
Years later, sexual violence still remains entrenched in conflict zones around the world and children are often the most vulnerable. Children suffering in conflicts are growing up in a world where they face the daily threat of rape and abuse and sexual violence is considered the 'norm'.
In Mogadishu, Somalia, Unicef teams treated more than 50 child survivors of sexual violence every single week in 2013. And in the Democratic Republic of Congo an average of 36 women and girls are raped every day - with children as young as six months old being targeted by armed groups.
Sexual violence devastates children's lives, resulting in long term damage. Sadly for many children the stigma and shame caused by rape can prevent them from reporting the crime or getting the community support they need. Sometimes children are just too scared to speak out for fear of retribution.
In countries affected by conflict - from the Democratic Republic of Congo to Somalia - sexual violence can create vicious cycles of abuse and poverty that pass down generations.
The long term physical and psychological damage of abuse can prevent children reaching their full potential, so they earn significantly less in the future and remain trapped in poverty. Sexual violence destroys not only the future of those who are affected but also those of their children to come.
Even long after conflict is over, sexual violence can remain embedded in culture. In post-conflict Liberia for instance, estimates indicate a staggering 87 per cent of children have experienced some form of sexual violation.
When a child has experienced rape or abuse, they need vital support to help them come to terms with their experiences. Psychological and medical assistance along with schooling and safe spaces are essential. Child survivors often need this support for an extended period and these programmes urgently need more funding.
Improving justice too is imperative. Too many armed groups in conflicts around the world assume they can get away with whatever crime they like - including the rape and sexual abuse of children. They hold little fear of being caught, or indeed punished for their despicable crimes. This culture of impunity is contemptible and must end.
Next week the Global Summit to End Sexual Violence in Conflict will be held in London. Foreign Secretary William Hague has shown true leadership in getting this crucial issue on the international agenda, including previously at the G8 and the UN.
The Summit will be the largest gathering ever brought together on this subject, with a view to creating irreversible momentum against sexual violence in conflict. Government Minsters from 148 countries are expected to attend, along with representatives from UN agencies and NGOs.
World leaders should now seize the opportunity to act for children at the Summit and put political will into action. Firm measures are needed to protect children in war zones from rape and abuse, as well as supporting child survivors and helping them seek justice.
The children of the Bosnian war still carry the trauma of sexual violence with them. It is time to act now to help ease the suffering of children who have survived these horrific crimes and to put concrete measures in place to prevent the next generation of children from experiencing the same horror.
Support UNICEF UK's campaign to help end sexual violence against children in conflict here - unicef.org.uk/endsexualviolence
Lord Paddy Ashdown is the Unicef UK President and a Lib Dem peer