The Northern Ireland Deputy First Minister Martin McGuinness has resigned. Under power-sharing procedures, First Minister Arlene Foster can no long continue in her role without Mr McGuinness.

The move therefore means power-sharing has effectively collapsed and will trigger an election for the Northern Ireland Assembly.

His resignation comes in protest at Ms Foster following allegations she mishandled a government scheme which cost the taxpayer more than £400m. Known as the 'cash for ash' scandal, it has been alleged that the scheme, which was set up in 2012 to encourage Northern Irish businesses to use renewable energy sources, had serious flaws which meant they were given a financial incentive to pointlessly burn fuel.

Ms Foster's DUP colleague Jonathan Bell broke party ranks to speak out against her, telling local media that she told officials to alter documents related to the scheme to minimise her appearance of responsibility. She strongly denies the allegations and says she has been unfairly represented in the media. She has refused to resign.

The scandal has dominated Northern Irish politics since the allegations emerged in November.

Smaller parties at Stormont tabled a motion of no confidence against her, however the petition failed.

This weekend, Sinn Fein leader Gerry Adams signalled the party could withdraw Mr McGuinness in order to make Ms Foster's position untenable.

In a resignation letter sent to Stormont speaker Robin Newton, Mr McGuinness states: “The First Minister has refused to stand aside, without prejudice, pending a preliminary report from an investigation.

“That position is not credible or tenable. Therefore it is with deep regret and reluctance that I am tendering my resignation as Deputy First Minister with effect from 5pm on Monday, 9 January 2017.

“I have urged Arlene Foster to stand aside without prejudice to ensure confidence in the necessary investigation and in the wider public interest. These institutions only have value if they enjoy the confidence and support of the people they were established to serve.

“They only have meaning if are delivering fairly for all our people based on the principles of equality and mutual respect on which they were founded.

”Over the last 10 years I have worked with DUP leaders and reached out to unionists on the basis of equality, respect and reconciliation.

“Over this period the actions of the British government and the DUP have undermined the institutions and eroded public confidence

”Sinn Féin will not tolerate the arrogance of Arlene Foster and the DUP. Sinn Féin wants equality and respect for all. That is what this process must be about.

“Today I tendered my resignation.Today is the right time to call a halt to the DUP’s arrogance.

“There will be no return to the status quo.”

In response, Ms Foster issued a statement, she said: "I am disappointed that Martin McGuinness has chosen to take the position he has today. He actions have meant that, at precisely the time we need our government to be active, we will have no government and no way to resolve the RHI [Renewable Heat Initiative] problems.

"It is clear that Sinn Fein's actions are not principled, they are political.

"Let me make it clear the DUP will always defend unionism and stand up for what is best for Northern Ireland and it appears from the Deputy First Minister's resignation letter that is what annoys Sinn Fein the most."

In a statement, Republic of Ireland Foreign Minister Charlie Flanagan responded to Mr McGuinness' resignation, saying: "The substance of the RHI controversy is very much a matter for the devolved Executive and Assembly. However, the Government is very mindful of the need to protect the integrity of the principles and institutions of the Good Friday Agreement. In this regard, both the effective functioning of those institutions and respecting the principles of partnership and equality are of critical importance.

“If, as appears likely, new elections to the Assembly will now be required, it behoves all parties to act responsibly in word and deed, so that the political institutions of the Agreement will not be damaged in the longer term.

“I have spoken this afternoon to the Deputy First Minister and to the Secretary of State for Northern Ireland. As a co-guarantor of the Good Friday Agreement, the Irish Government will continue to work with the British Government and the political parties to advance political stability, reconciliation and economic prosperity in Northern Ireland.”

Following Mr McGuinness' announcement, Mr Adams tweeted his support for his decision. He wrote: “Ten years of valient [sic] service in Office of First & Deputy First Minister Martin McGuinness signs resignation letter.” He added: “GRMA chara”, meaning “thank you, friend” in Irish.