I attended a very special memorial service in St Giles Cathedral, Edinburgh, last Friday. Like similar events across Europe, we were remembering the Srebrenica Genocide of July 1995: the cold blooded murder of 8327 Bosnian men and boys by Bosnian Serbs, and the rape and abuse of the women and girls left behind.

I listened to the Mothers of Srebrenica speak during the service. Their pain still raw. Their anger still deep. We let them down. They had moved into a safe protected UN area but were delivered into the hands of the advancing troops and were powerless to escape or resist.

A year earlier in Rwanda the world also looked away as nearly 1 million Rwandans were murdered by organised government militias and by their neighbours in the genocide of the Tutsis.

As UN Secretary General from 1997, Kofi Annan was determined to learn the lessons from these atrocities and prepare the United Nations for the 21st century. Between 2000 and 2005, the international community came together to agree a norm that would form the basis for humanitarian intervention in situations of armed conflict and protect citizens from ‘genocide, war crimes, ethnic cleansing and crimes against humanity’. The principle was called Responsibility to Protect (R2P).

It is ten years since the United Nations World Summit in September 2005, the largest gathering of global leaders in history, unanimously backed R2P. The three pillars of the principle ensured States carry the primary responsibility for protecting populations, the international community has a responsibility to encourage and assist States in fulfilling this responsibility and the international community also has a responsibility to use diplomatic, humanitarian and, if necessary, interventionist means to protect populations from these crimes.

Ten years on from the establishment of R2P, it is important to reflect. UN Secretary General Ban Ki Moon observed that in 2011 ‘the responsibility to protect came of age; the principle was tested as never before. The results were uneven, but at the end of the day, tens of thousands of lives were saved. We gave hope to people long oppressed’.

The results have however been inconsistent. There are demands for ‘responsibility while protecting’, capacity building has not been enough of a priority for international donors, atrocities go on, permanent members of the UN Security Council block action despite evidence of human suffering.

Here in the UK, and in the European Union, we could do more to build atrocity prevention and R2P principles into our diplomatic, development and security strategies.  And in 2015, the new Sustainable Development Goals to be agreed in September will hopefully include Goal 16 with its explicit commitment to capacity building for conflict prevention and peace. So we can and we must do more.

For me, the Responsibility to Protect principles remain the best and only way to handle these challenges internationally. But their application has to be consistent; early warnings cannot be ignored; capacity building must be more of a priority; and the future of the veto as a means of stopping action must be up for debate. For past failures, if we are to pay proper respect to those who paid with their lives, or the painful memories for those left behind, then we must review and improve how we put them into action in future.

The Mothers of Srebrenica and the survivors in Rwanda deserve no less.