Northern Ireland’s police chief has warned that mob rule must not be allowed to win as he stressed the need to find a peaceful resolution to the Drumcree parading dispute.

Jon Boutcher said he would continue to seek a way to facilitate an Orange Order march down the predominantly nationalist Garvaghy Road in Portadown, but he made clear he is not prepared to do it at any cost, highlighting his overriding responsibility is keeping people safe.

The Police Service of Northern Ireland chief constable expressed concern his officers had “once again become the shock absorber of our society”.

Secretary of State Sir Chris Bryant suggested a deal is “tantalisingly close”, but he also warned he is not sure whether it will be possible.

Speaking to the media outside Hillsborough Castle following meetings with the Orange Order and Garvaghy Road Residents Coalition on Wednesday, Sir Chris said they had not reached the end of the process yet.

“I’m not sure whether it’s possible and I would just appeal to everybody, including the wider community, not just the people I have been meeting in the room, that people are going to have to search deep in their souls for another chunk of compromise if we’re going to get to a successful long-term resolution of the situation,” he said.

“I personally – and everybody in my team – is personally working flat-out to try and get to a successful resolution, and I think that is tantalisingly close if everybody can just go that extra mile.”

Meanwhile, Mr Boutcher also confirmed there is a large-scale criminal investigation under way into a mass unlawful protest that blocked the Garvaghy Road on Sunday in an attempt to prevent the parade going ahead.

Several high-profile politicians, including Northern Ireland’s First Minister Michelle O’Neill, participated in the unnotified protest.

The Drumcree parading dispute, which was associated with violent disorder during the Troubles, has been reignited after the Parades Commission adjudication body granted permission for a limited Orange Order parade down the Garvaghy Road for the first time in almost 30 years.

It was supposed to take place at 8am on Sunday morning but loyal order members were halted by police after more than 1,000 people gathered on the Garvaghy Road to block the route.

Orangemen have been waiting since Sunday to conduct the parade. They have tried on several occasions to start the procession, but have been prevented by police each time.

The permission to parade along the route was confirmed after three court challenges across Saturday and into the early hours of Sunday.

The dispute is now set to return to the courts, with lawyers for the Garvaghy Road residents having launched a fresh legal bid to try to prevent the controversial march from going ahead.

Their latest legal challenge, which argues the Parades Commission “materially misdirected itself” on the police assessment of the potential for disorder, is set to be heard on Friday.

Mr Boutcher’s offer to meet representatives on both sides of the dispute comes as Sir Chris continues talks with Orangemen and nationalist residents at Hillsborough Castle.

Mr Boutcher said: “My officers and our mutual aid colleagues have and will continue to police Drumcree and our communities independently and impartially.

“The principle objective in achieving the Parades Commission determination is to do so peacefully.

“People shouting at me has absolutely no effect on my judgment and they would do well to learn that. My overriding responsibility is to keep people safe.

“We continue to seek to achieve compliance with the Parades Commission determination, obtained by the Orange Order, and have created the space for the ongoing talks at Hillsborough with the parties involved.

“To be clear, the upholding of the Parades Commission determination does not come at any cost.

“The outstanding officers of the PSNI and our mutual aid colleagues will not allow society to implode into violent disorder and mob rule must not be allowed to win.

“A large-scale criminal investigation is under way regarding unlawful protest on the Garvaghy Road. I have given a clear direction regarding prioritising the evidence gathering and a criminal justice process.

“We all need to focus our efforts on resolving this situation once and for all. I will not be part of this society moving backwards.”

On Wednesday, a senior Orangeman said the Northern Ireland Secretary had been “left in no doubt” the law must be applied to allow their parade in Drumcree to proceed.

The Orange Order delegation was the first to arrive at Hillsborough Castle for talks with Sir Chris.

The group was made up of Portadown District Master Nigel Dawson, deputy District Grand Master Alastair Power and their legal adviser Jamie Bryson.

They left around two hours later.

Mr Dawson said: “We have just concluded another meeting with the Secretary of State.

“Obviously the contents of these meetings remain confidential.

“However, the Secretary of State has been left in no doubt that our continued position is that he must, and the chief constable, must apply the law in relation to the positive determination issued by the Parades Commission and reinforced by the High Court.”

A delegation of residents from the Garvaghy Road later met with the Secretary of State.

The group was led by Breandán Mac Cionnaith, from the Garvaghy Road Residents Coalition.

Asked what his message for the Northern Ireland Secretary was, Mr Mac Cionnaith said: “I think you know that.”

The two groups are not meeting face to face, but instead held separate meetings with Sir Chris in the Edenderry Room in the castle.

Efforts to call off the parade were brought to Government Buildings in Dublin on Tuesday where Sinn Féin leader Mary Lou McDonald and deputy leader Ms O’Neill met Taoiseach Micheál Martin and Tánaiste Simon Harris.

Ms O’Neill has faced criticism from unionists after she and senior colleagues were among the large crowd that blockaded the Garvaghy Road on Sunday.

On Wednesday morning, TUV MLA Timothy Gaston said he had tabled exclusion motions at the Northern Ireland Assembly for Ms O’Neill and other Sinn Féin ministers in the Stormont Executive.

He claimed they “no longer enjoy the confidence of the Assembly” after “participating in the unlawful protest on the Garvaghy Road on September 27 which prevented a permitted parade from proceeding”.

He is calling for them to be excluded from holding office as a minister or junior minister for a period of 12 months.

Under parading laws in Northern Ireland, protests must be notified to, and approved by, the Parades Commission adjudication body.

The PSNI has confirmed Sunday’s protest was unnotified and therefore unlawful.