Members of the Northern Ireland assembly walked out of the chamber en masse as the first minister, Arlene Foster, prepared to make a statement before a vote on her leadership.

The Social Democratic and Labour party (SDLP) has tabled a motion of no confidence in Foster over a renewable energy scheme that could cost the taxpayer up to £400m.

All of the main opposition parties are backing the motion. If it wins the support of Sinn Féin, the DUP’s partner in the power-sharing executive, the government would fall and there would be fresh elections in the new year.

Opposition members objected to Foster making the statement to the assembly without the backing of her deputy, Sinn Féin’s Martin McGuinness. Stewart Dickson, an Alliance party MLA, said the assembly’s rules had been “stretched to their limit”.



After the walkout by members of all parties bar Foster’s DUP, proceedings in the devolved parliament were suspended for half an hour.



When they resumed, still with only DUP members present, Foster read a 15-page statement in which she said the failure to impose a cap on payments under the energy scheme was the biggest regret of her political career.

She said she had not received any indication that controlling the costs of the scheme was an urgent priority.

Last week the former Stormont minister Jonathan Bell accused fellow DUP members of delaying the closure of the scheme. He alleged that DUP advisers had tried to “cleanse the record” of any links between Foster and the decision-making process that had lead to the scheme’s creation.

Foster said she had no role in the scheme after she changed jobs from enterprise minister to finance minister in May 2015. The enterprise department was in charge of running the scheme.

Foster said she supported the creation of an independent public inquiry into the scheme. “My priority is to ensure lessons learned and reduce projected cost,” she said. “I am not immune to considerable anger and indeed feel it too. I will not shirk away from my responsibility.

“The record shows I have worked hard for Northern Ireland and will continue to do so. The record will show that instead of whipping up a media storm, I have been working to resolve this issue. That’s what politics is about.”

Before Foster’s statement, McGuinness repeated his suggestion that she should step down temporarily to allow for an independent inquiry

“There is no credibility in an investigation established solely by the DUP or in the selective release of some documents by DUP departments,” he said. “An independent investigation is the only way to establish the truth of what has occurred and to begin to restore public faith in the institutions.”

He said Foster’s statement to the assembly did not have his authority or approval as deputy first minister. “She is speaking in a personal capacity and not in her role as first minister,” McGuinness added.

The renewable heating incentive scheme was set up in November 2012 to encourage the use of renewable energy sources. Critics say it offered inflated financial incentives to farms and businesses to use biomass boilers that mostly burned wood pellets.

In February it was alleged that the scheme was being abused and that one farmer had made £1m from renting an empty shed.

In the summer Northern Ireland’s auditor general, Kieran Donnelly, concluded that there was “no upper limit on the amount of energy that would be paid for. The more heat that is generated, the more is paid.”