The death of my friend and comrade Martin McGuinness has left a deep void. It is a huge blow to all of us who knew and loved him, especially his wife and family. Martin was an extraordinary human being. Funny, caring, a committed family man, a keen fisherman, an enthusiast for all kinds of sport from cricket to hurling. He loved Derry. The city – along with his wife, Bernie, his family and his mother, Peggy – moulded him into the complex, compassionate, warm, human being he was.

Martin was also a deeply committed Irish republican activist who in his youth was confronted by the naked sectarianism and injustice of the British state in Ireland, and stood strong against it. As a result he was imprisoned and spent long periods on the run.

Reading and watching some of the media reporting of his life and death, one could be forgiven for believing that Martin, at some undefined point in his life, had a road to Damascus conversion and abandoned his republican principles, his former comrades in the IRA and joined the political establishment.

To suggest this is to miss the truth of his leadership and the essence of his humanity. There was not a bad Martin McGuinness or a good Martin McGuinness. Martin believed in freedom and equality. He resisted those who withheld these by military means, and then he helped shape conditions in which it was possible to advocate for these by unarmed strategies.

Martin was a committed republican who believed that the British government’s involvement in Ireland and the partition of our island were at the root of our divisions. Along with others of like mind, he understood the importance of building a popular, democratic, radical republican party.

In this way he helped chart a new course, a different strategy. This involved taking difficult initiatives to make political advances. Our political objectives, and our republican principles and ideals did not change. On the contrary, these guided us through every twist and turn of the peace process.

Martin also understood that reconciliation and peace-building meant reaching out to others. He played a leadership role in this throughout his time in elected office, and especially from 2007, when he and Ian Paisley became partners in a unique power-sharing arrangement.

Martin’s leadership and vision helped turn Sinn Féin into the largest political party on the island of Ireland. Our responsibility, now that he has gone, is to build on that legacy. To continue the work that he helped pioneer. That means building a new Ireland – a united Ireland – that embraces all its citizens on the basis of equality and respect.

Last November Sinn Féin launched “Towards a United Ireland”, a detailed discussion paper setting out the arguments for a United Ireland. It addresses the impact of partition on the island’s economy, on inward investment, on exports, on the health service, on the border region and much more. It takes head-on the argument that the people of the north and south cannot afford a united Ireland. It takes this on and demolishes it.

We have also argued that the British government accept the vote of the people in the north of Ireland to remain in the EU. Theresa May refused to do this. We propose that the north be accorded a special designated status within the EU. This will not change the constitutional issue but it will prevent a land frontier – a new hard economic border on the island of Ireland – between the EU and the British state.

The decision by the British government to trigger article 50 next week and commence the negotiations on Brexit; the assembly election results, which saw the unionist parties lose their electoral and assembly majority; and the warning by the Scottish first minister of a second independence referendum – all these are the context now for the necessary conversation on a new Ireland.

Martin is gone, and we will miss him. But he leaves behind a Sinn Féin party, stronger, better organised, and more electorally popular than it has been in almost 100 years. We have a cadre of young, energetic leaders who are as determined as my generation of achieving a united Ireland. It is a party more determined and more able than ever before to deliver on Martin’s goal of a new Ireland.