Northern Ireland's former first minister Arlene Foster "ordered" ex-minister Jonathan Bell to keep open a renewable energy scheme despite spiralling costs, an inquiry has heard.

Mr Bell claimed that he argued that was "folly", but insists he was overruled.

He was minister at the Department of Enterprise Trade and Investment from May 2015 to May 2016, which oversaw the Renewable Heat Incentive (RHI) scheme.

The initiative was intended to encourage businesses to switch from fossil fuels to green alternatives such as biomass.

By the summer of 2015 the cost to the taxpayer was beginning to spiral as firms realised how lucrative the incentives on offer were.

At one stage it was feared the scheme could cost the state hundreds of millions of pounds.

It caused a political row which culminated in the resignation of deputy first minister Martin McGuinness in January 2017 and the collapse of the power-sharing government at Stormont.

A public inquiry set up to examine what went wrong with the RHI scheme heard a claim today that Mrs Foster was giving mixed messages about closing it.

Mr Bell signed a directive on 22 January 2016 to shut the scheme.

But the inquiry heard that DUP special adviser Timothy Johnston "rescinded" his decision.

Mr Bell also claimed Mrs Foster "created a paper trail" calling for the scheme to be closed, but verbally, her and the DUP's special advisers were pushing for it to be kept open.

According to Mr Bell's evidence, the situation came to a head during a tense meeting between Mrs Foster and Mr Bell on 9 February.

"There was tension, the atmosphere was abusive, Arlene was very abrupt," Mr Bell told the inquiry.

Mr Bell (left) and his solicitor Denis Moloney arrive at the RHI inquiry
at Stormont parliament buildings

"I said minister, I have made the decision (to close the scheme), we had announced the decision and really are you going to place me in a position ... where in my view I am effectively asking a civil servant to do something that is wrong, and order them to do it. I wasn't prepared to do it.

"I did argue hard not to do it, but she ordered me to do it.

"She said, look, I am the first minister, you will follow my order. I am instructing you and reversing your decision.

"I felt bullied into taking the decision because I was taking the decision against my rational judgment".

Mr Bell said Mrs Foster said she wanted to keep the scheme open to consult further with industry.

"I thought that was totally unreasonable because we had a scheme that was out of control," he said.

Mrs Foster has given evidence to the inquiry that she was not proposing to reverse the decision to close the scheme completely, but to delay it for several more weeks.

Mr Bell's former special adviser Timothy Cairns told the inquiry the delay in closing the scheme was only to be for another two weeks.

During Mr Bell's evidence, the inquiry heard that several hours after the meeting, there was a second friendlier meeting between the two.

At that meeting, Mr Bell said Mrs Foster asked for a two-week extension to the scheme which he agreed to.

Mrs Foster and the two advisers have told the inquiry they believe Mr Bell opposed a two-week extension to the closure of the scheme because it made him look foolish.

Mr Bell completed his two days of evidence by telling the panel he sacrificed his political career to stop the overspend on RHI.

"My only motivation was those hundreds of millions of pounds to get back into the health service and our education system.

"For that, I knew I would have sacrificed my political career.

"I had two objectives, one an inquiry to establish the truth, we have got that and I have every confidence in this panel, including any criticism you may or may not have of me, for which I'll apologise for in advance.

"But secondly to ensure these costs were changed and that money is now available.

"For both of my objectives, I have achieved them".

The inquiry is scheduled to hear evidence from former special adviser Timothy Cairns when it resumes on Tuesday.