A DUP MP says unionist voters are angry at Michelle O’Neill over her role in the Garvaghy Road protests and says it “cannot be business as usual” at Stormont.

Carla Lockhart said the DUP has it “within its gift to remove” O’Neill as Northern Ireland’s first minister.

On Friday, the secretary of state banned the Portadown District Lodge from marching down the mainly nationalist Garvaghy Road. His decision was welcomed by nationalist politicians but unionists have criticised the move.

O’Neill is one of a number of Sinn Féin politicians who have confirmed they received letters from the Police Service of Northern Ireland (PSNI) investigating protests over the Drumcree parading dispute.

Speaking outside Drumcree Church on Saturday, Lockhart said her constituents are angry.

“They’re angry at the chief constable for allowing lawlessness to win, for allowing the mob to dictate,” she said.

“They’re angry at the secretary of state for his intervention, but the most palpable anger is at Michelle O’Neill, this self-proclaimed ‘first minister for all’ for breaking the law flagrantly on the Garvaghy Road, and thumbing her nose at unionism and at the Orange Order and at this community.”

Police had repeatedly warned those taking part in the unnotified protest that they could be liable for arrest.

O’Neill has defended her involvement, saying she was standing with the local community in opposition to an Orange Order parade through the area.

She previously dismissed a call from the DUP to resign over her role in protests telling the assembly she was “proud” to stand with the residents and “will continue to stand with them”.

The DUP (Democratic Unionist Party) share power with Sinn Féin in the Northern Ireland Executive, but Lockhart says it can no longer be business as usual.

“You can not continue to engage with someone who is so blatant in her disregard and disdain for a large section of this community,” she said.

“Very clearly it cannot be business as usual at Stormont.”

Lockhart says her party must take action against O’Neill.

“People want to see consequences, and we have said very clearly, profound consequence, and therefore we should use whatever is in our armoury to ensure that Michelle O’Neill, the person who really is supposed to be that first minister for all, as she claims, is dealt with in the appropriate way,” she added.

The DUP could remove O’Neill from the first minister’s position if the deputy first minister quits.

That role is held by Emma Little-Pengelly, but that seems unlikely.

DUP leader Gavin Robinson said that Lockhart “is right that the options are there”, but stopped short of suggesting his party may collapse the executive.

Speaking on BBC News NI’s Sunday Politics programme, he echoed Lockhart’s words that “it will not be business as usual”, but added: “does collapsing Stormont bring the Orangemen home”?

Robinson also called on the chief constable to “be very open” in telling the public “what was the threat that he perceived” when he asked the secretary of state to review the Parades Commission’s determination.

He said he “certainly wouldn’t” want Sir Chris to govern Northern Ireland if the executive did collapse.

TUV leader Jim Allister said he was “disappointed” by the DUP’s “limp response”.

He said Robinson promised “profound consequences, and then when he’s asked what they are, it emerges that the Emperor of the DUP has no clothes”.

Allister accused the DUP of “doing nothing”, which he said showed “there are no political consequences” for Sinn Féin.

Sinn Féin assembly member John O’Dowd rejected claims that the move to ban the parade went in favour of his party, saying “the decision went in the way of the residents” who he said have “faced an awful four weeks” since the application to walk was lodged.

O’Dowd, who is also finance minister in the executive, was one of a number of Sinn Féin politicians who joined a protest with residents on the Garvaghy Road.

On Thursday, the police said they had begun issuing letters inviting people “reasonably suspected” of committing offences linked to the protests to interview.

Speaking on BBC News NI’s Sunday Politics programme, O’Dowd said: “I own my decision”, adding that he thinks it was “the right thing to do”.

“I got into politics to stand against the intimidation of communities such as the Garvaghy Road, who went through hell and high water over many, many years.

“I stood with the people of the Garvaghy Road. I will continue to stand with the people of Garvaghy Road because it was the right thing to do.”

He added that he believes the community responded in “a peaceful, democratic way” to the decision to approve a march on 27 September.

“I would appeal, not only to Gavin, but maybe hopelessly to Carla and others, to calm their language and to show responsible leadership and calm leadership at this stage,” he added.

“I don’t think that continued demonisation or an attempt to criminalise the community of the Garvaghy Road is an appropriate way forward.

“What we need in Portadown is reconciliation.”

The Parades Commission ruled that the march on Sunday 27 September could go ahead with restrictions in place.

That parade did not happen and, after a series of legal challenges and talks between residents and Orangemen, the secretary of state banned the procession on Friday.

Sir Chris Bryant said his decision to ban the Drumcree parade “was in the best interests of peace”.

The secretary of state said he received advice from the PSNI chief constable that allowing the procession to go ahead could lead to serious injury, disorder and wider unrest.

On Saturday, a High Court judge said a legal appeal by Orangemen following the secretary of state’s decision was not an emergency case and adjourned the hearing until Monday.

Lockhart said the 35 Orangemen from Portadown District Lodge had “stood lawfully” for the last two weeks on Drumcree hill.

“I’ve been on this hill from I was 10 years of age, it means something to me. It means a lot to my constituents here in Upper Bann,” she said.

So does the Upper Bann MP still have confidence in her own party?

“I have confidence that I will ensure that my constituents’ voices are heard within the party, and I will ensure that I continue to represent the views here in Portadown,” she said.