Long-time Sinn Fein colleague Gerry Adams led tributes to Martin McGuinness, describing him as a "passionate republican who worked tirelessly for peace and reconciliation and for the reunification of his country".

Mr Adams posted Irish folk singer Luke Kelly's Song for Ireland along with the tweet "A song for Martin McGuinness. I measc Laochra na n-Gael go raibh a anam dilis", which translates as "Among heroes of Gael he had a faithful soul".

Labour MP for Birmingham Yardley Jess Phillips posted on Twitter: "People can do good and bad, things aren't simple. People should be neither reviled or worshipped. I wish he'd helped my constituents find peace."

READ MORE: Former Tory Cabinet minister Norman Tebbit hopes ex IRA commander Martin McGuinness is in 'particularly hot and unpleasant corner of hell for the rest of eternity'

But Conservative MP for Mid Bedfordshire Nadine Dorries tweeted: "I hope God forgives this man and grants him a place in heaven - however, it will be hard for many to shed tears upon hearing this news."

In a statement, President of Ireland Michael D Higgins paid tribute to the ex-IRA commander's "immense contribution to the advancement of peace and reconciliation in Northern Ireland".

He said: "The world of politics and the people across this island will miss the leadership he gave, shown most clearly during the difficult times of the peace process, and his commitment to the values of genuine democracy that he demonstrated in the development of the institutions in Northern Ireland.

"As President of Ireland, I wish to pay tribute to his immense contribution to the advancement of peace and reconciliation in Northern Ireland - a contribution which has rightly been recognised across all shades of opinion."

He added: "In addition to his services in public life, as an inclusive believer in community in all its forms he will also be remembered for his warm support for Derry GAA and Derry FC.

"His death leaves a gap that will be difficult to fill. May he rest in peace."

READ MORE: Martin McGuinness: The IRA commander turned peacemaker who shook hands with Queen

Former Northern Ireland secretary Lord Hain said Mr McGuinness was "absolutely crucial" to the peace process.

"He had the grassroots credibility of a republican leader and former IRA commander, that could enable him, along with Gerry Adams, to take his followers, to take republicans, from the past of terror and horror into a democratic future, which is what he did," Lord Hain told the BBC Radio 4 Today programme.

"Sometimes in the history of conflicts - and, goodness me, the island of Ireland has been involved in centuries of conflict with Britain - you need leaders who can rise above their past and, at that point, Martin McGuinness certainly stood the test and proved to be an indispensable figure."

The Labour former cabinet minister revealed that Mr McGuinness also had an unlikely love of the England cricket team.

"I discovered he was a fan of the England cricket team - this was a hardline republican - but I realised watching the Ashes series on the television in the corner of my office in Stormont Castle that he actually was following the England cricket team, he knew all the players," Lord Hain said.

Good Morning Britain host Piers Morgan tweeted: "RIP Martin McGuinness, 66."

In a later post, he compared Mr McGuinness to former president of South Africa and anti-apartheid activist Nelson Mandela, saying: "Both men renounced violence to forge peace. The comparison is valid."

Former Prime Minister Tony Blair said: "I am very sorry to learn of Martin's death and send his family my deep sympathy and condolences.

"I grew up watching and hearing about the Martin McGuinness who was a leading member of the IRA engaged in armed struggle. I came to know the Martin McGuinness who set aside that armed struggle in favour of making peace. There will be some who cannot forget the bitter legacy of the war. And for those who lost loved ones in it that is completely understandable. But for those of us able finally to bring about the Northern Ireland peace agreement, we know we could never have done it without Martin's leadership, courage and quiet insistence that the past should not define the future.

READ MORE: Son of IRA Enniskillen bombing victim 'will always remember Martin McGuinness as terrorist'

"After first meeting in Northern Ireland and then again shortly after in Downing Street - an historic meeting, between a British PM and the Republican leadership in the Cabinet room where so much Irish history had been made - he explained at length to me the causes of Republican grievance. I listened. We talked. And as the meeting went on he explained why he thought despite all the grievance there was a chance for peace.

"Over the years - through the arduous negotiation of the Good Friday Agreement - and for the years after it, I got to know Martin well. We met many, many times and as the trust grew between himself, my team, Gerry Adams and their team, so the discussions became increasingly open, frank and therefore productive.

"By the time that extraordinary day arrived in 2007 after almost a decade of hard work where we could witness the - to my generation - incredible sight of he and Ian Paisley sitting down together in Government, the transition of Martin to reconciliator was complete.

"Whatever the past, the Martin I knew was a thoughtful, reflective and committed individual. Once he became the peace maker he became it wholeheartedly and with no shortage of determined opposition to those who wanted to carry on the war.

"I will remember him therefore with immense gratitude for the part he played in the peace process and with genuine affection for the man I came to know and admire for his contribution to peace."

Alliance Party leader Naomi Long expressed her gratitude to the former deputy First Minister's "willingness to work with others" in a Facebook statement.

She wrote: "I want to pay tribute to the hard work and dedication Martin invested as an MLA and as deputy First Minister to serving not only his constituents, but Northern Ireland.

"Whilst our politics were very different and while his past is well documented, the compromises he made, the leadership he demonstrated and his willingness to work with other despite those differences as part of the peace process helped secure the peace we all now enjoy.

"For that, we are grateful and our best tribute to him would be to do all in our power to secure that peace and progress for future generations."

Northern Ireland Secretary James Brokenshire said: "I want to extend my sympathy and sincere condolences to the family of Martin McGuinness at this difficult time.

"Martin's personal journey and the clear influence he had on others in the republican movement were instrumental in shaping political institutions in Northern Ireland founded on exclusively peaceful and democratic means.

The Herald:

"While not forgetting the past, no-one can doubt the essential role he played in helping to secure the power sharing arrangements and political progress in Northern Ireland. Martin's commitment to reconciliation and understanding across communities was a significant factor.

"Whilst passionate and robust in his politics, on a personal level I always found Martin to be thoughtful and reflective and appreciated the personal consideration he showed. The importance of family and his home in Derry shone through.

"Martin will be remembered for his contribution to politics in Northern Ireland and particularly during his near ten years as deputy first minister."

Former Northern Ireland secretary John Reid said: "Martin McGuinness's passing is a sad loss to his family, friends and to Northern Ireland as a whole. He was an indispensable part of the peace process.

"Though Martin remained a staunch Republican, he had the courage to change, to compromise, to abandon violence, to embrace old enemies, to promote reconciliation and he made a massive contribution in shaping a better future for everyone in Northern Ireland."

First Minister of Wales Carwyn Jones said: "Martin was vital in bringing peace to Northern Ireland. I worked closely with him over many years at British Irish Councils, Joint Ministerial Councils and beyond.

"When he spoke, people listened. That presence explains much about how he was able to build bridges across the political divide. My thoughts are with his family and friends today."

Irish Taoiseach Enda Kenny said: "I was deeply saddened to hear of the death of Martin McGuinness today. His passing represents a significant loss, not only to politics in Northern Ireland but to the wider political landscape on this island and beyond.

"Martin will always be remembered for the remarkable political journey that he undertook in his lifetime. Not only did Martin come to believe that peace must prevail, he committed himself to working tirelessly to that end.

"Martin was one of the chief architects of the Good Friday Agreement and he worked resolutely in the years that followed it in pursuit of its full implementation. I got to know Martin well in recent years, including through our working together in the North South Ministerial Council. His commitment to securing enduring peace and prosperity for all of the people of Northern Ireland was unwavering throughout this time. He strove to make Northern Ireland a better place for everyone, regardless of background or tradition.

"Above all, today is an especially sad day for Martin's family - his wife Bernie, and his children - and for the people of Derry, who held a special place in Martin's heart.

"My deepest sympathies are with all of them at this sad and difficult time."

Labour leader Jeremy Corbyn said on Twitter: "Martin McGuinness played a huge role in bringing about peace in Northern Ireland. He was a great family man and my thoughts are with them."

Former Irish taoiseach Bertie Ahern, who was central to the Good Friday Agreement being signed, described Mr McGuinness as an extraordinary person, honest in his efforts and an upfront negotiator.

"In negotiations when there is a lot at stake and it can't be a winner takes all Martin understood compromise," he told RTE Radio.

"He listened and he was able, I think, to arbitrate between different points of view."

The Herald:

Mr Ahern said he could "totally" understand why Mr McGuinness joined the IRA but also put his life on the line to pursue peace.

"I think Martin McGuinness would have been happier following Derry GAA club or Derry City or fly fishing in Donegal," he said.

"He was a good person in my view.

"He moved from a very difficult past where he took a particular side and he was a good person to negotiate with and certainly I considered him as a good friend as we went through 25 years of discussions."

Former Scotland first minister Alex Salmond tweeted his "sympathy and condolences" to Mr McGuinness' family, along with a statement that recalled his visit to Northern Ireland at the launch of the Stormont powersharing agreement.

READ MORE: Martin McGuinness: The IRA commander turned peacemaker who shook hands with Queen

"As first minister of Scotland, I was asked by Ian Paisley and Martin McGuinness to go to Northern Ireland in 2007 to support their new powersharing administration by addressing the Northern Irish Assembly," he said.

"I gladly did so and found a remarkable partnership, which was the anchor of the institutions consolidating the peace process.

"The friendship which developed between them was real, enduring and profound, private as well as public and allowed Northern Ireland to move away from violence. They were both solid friends of Scotland.

"That political journey was accompanied by Martin McGuinness' own personal journey. It is why it is right to both mourn his passing and recognise his contribution today. My sympathy and condolences go to Martin's family."

Traditional Unionist Voice party leader Jim Allister said Mr McGuinness had taken secrets about his IRA past to the grave.

"Naturally, the passing of anyone causes grief and sorrow to their family and friends. All such families deserve condolences," he said.

"In the case of Martin McGuinness, he lived many more decades than most of his victims."

He added: "So today my primary thoughts are with the many victims of the IRA who never reached the age of 66; of men and women who never got to see their grandchildren because their lives were cut short by murderous republicanism; of children stolen from their parents and grandparents by the organisation in which McGuinness was a commander."

Shadow Northern Ireland secretary Dave Anderson said: "On behalf of myself and my colleagues I would like to extend condolences to the family, friends and loved ones of Martin McGuinness on his sad passing today.

"His political journey was as unique as Northern Ireland's itself and demonstrates the great change seen throughout the peace process.

"Whilst our politics may not have been the same, it is clear to all that Martin played a key role in helping to bring forward the peace we see in Northern Ireland today and for that we should all show our gratitude."

The Herald:

Conservative former shadow Northern Ireland secretary Owen Paterson said: "I served as Shadow Secretary of State for Northern Ireland from 2007 to 2010 and as Secretary of State from 2010 to 2012.

"During that time, Martin McGuinness was Deputy First Minister of Northern Ireland, pursuing his lifelong political aim of a united Ireland by peaceful, democratic means.

"Although we did not agree on the future of Northern Ireland, we built up a perfectly cordial and constructive relationship. However, I cannot condone his earlier years, in which he pursued his political ambitions through a shockingly violent terrorist campaign.

"This caused death, destruction and ruined many lives. Whilst his later renunciation of violence was undoubtedly vital in fostering peace among the wider republican movement, we should not forget the many victims of terror who were not given such a choice."

The Chief Constable of the Police Service of Northern Ireland, George Hamilton, said: "I was saddened to hear of the death of former deputy first minister Martin McGuinness. I extend the sympathies of the Police Service to his wife and family at this sad time.

"Our society suffered grievously throughout our troubled history, and many police officers and their families are among those who suffered.

"But Martin McGuinness believed in a better future for our community, and this is a vision shared by policing.

"Martin's journey in life challenges all of us who care about the future to be prepared to change, to demonstrate leadership, and to work to understand the world, not just from our own perspective, but from the perspectives of everyone in our community."

Donald Tusk, President of the European Council, said: "Sad to learn of sudden passing of Martin McGuinness. His contribution to peace in Northern Ireland will endure."

Former prime minister Sir John Major said: "For too many years, too many people lost their lives over the Troubles in Northern Ireland.

"Martin McGuinness realised that - if one wishes to secure long-term peace - negotiation must always prevail over violence. In a mixed legacy, that stands to his credit.

"Let that be his epitaph."

And another former PM, David Cameron, said: "Despite our differences I enjoyed working with Martin McGuinness. He wanted politics to work in Northern Ireland and helped make it happen."

European Council president Donald Tusk tweeted: "Sad to learn of sudden passing of Martin McGuinness. His contribution to peace in Northern Ireland will endure.

"Ar dheis De go raibh a anam," he added.

Former prime minister David Cameron also tweeted following the former deputy first minister's death: "Despite our differences I enjoyed working with Martin McGuinness. He wanted politics to work in Northern Ireland & helped make it happen."

Scotland's First Minister Nicola Sturgeon said she got to know Mr McGuinness recently through their work in the British Irish Council and the Joint Ministerial Committee.

"Martin will be remembered for his commitment, alongside that of Ian Paisley, to bringing peace and reconciliation to Northern Ireland," Ms Sturgeon said.

"He grew up in Northern Ireland's troubled past - but without his hard and brave work to bridge the divide, peace would not have been achieved.

The Herald:

"I had the opportunity in recent years to get to know Martin through our work in the British Irish Council and Joint Ministerial Committee - his deep understanding of both the importance and fragility of the peace process, and also his optimism for the future, was obvious to all.

READ MORE: Martin McGuinness: The IRA commander turned peacemaker who shook hands with Queen

"While he had been unwell for a few months, his untimely death will still come as a shock to many and my thoughts and sympathies are with his wife, wider family and friends."