Canadian historian Margaret MacMillan explores how the law and international agreements have attempted to address conflict in a programme broadcast by BBC Radio 4 this morning.

Speaking to an audience at the Parliament Buildings at Stormont in Belfast, Professor MacMillan outlines how both states and the people have sought to justify warfare - from self-defence to civil war - focusing on examples from Irish and British history. The programme, including a question and answer session, is presented by Anita Anand.

The programme also includes testimony from former IRA and UVF paramilitary fighters, as well as former Northern Ireland police officers.

Managing the Unmanageable will be broadcast again on BBC Radio 4 on Saturday 21 July, 10:15pm and is available on BBC iPlayer.