Government negotiations with the DUP over post-Brexit trading arrangements are in their final phases and in a “positive space”, Northern Ireland Secretary Chris Heaton-Harris has told MPs.

Pressed at the Northern Ireland Affairs Committee on whether he was prepared to take action to end the Stormont stalemate if agreement with the largest unionist party in Northern Ireland could not be reached, Mr Heaton-Harris said he was not minded to change the principle of consent enshrined in the Good Friday Agreement.

The DUP has been blocking powersharing for more than a year in protest at the internal UK trade barriers created by Brexit’s Northern Ireland Protocol.

The party says the Windsor Framework deal struck by the EU and the UK to reform the protocol does not sufficiently address its concerns and has made clear it will not accept a return to devolution until the Government provides further assurances, by way of legislation, over Northern Ireland’s place in the UK internal market.

Talks between the DUP and the Government have been ongoing over the summer.

Committee chair Simon Hoare asked the Northern Ireland Secretary to provide a “robust and frank” update on the negotiations and if a deal was imminent.

Mr Heaton-Harris said his primary focus was to get the Stormont Executive back up and running.

He added: “We have had long and ongoing talks over the summer.

“They are in their final phases and in a much more positive space than they have been previously.”

Mr Hoare asked if a legislative reassertion of the integrity of the Union would be included in the King’s speech this autumn.

Mr Heaton-Harris said: “I have always said if we can get that legislation correct then we will introduce it.

“Until I know that it is part of the answer to the question, it doesn’t exist.”

The devolved powersharing institutions at Stormont cannot operate without the support of the largest unionist and nationalist parties in Northern Ireland.

SDLP committee member Claire Hanna asked the Northern Ireland Secretary if he had a plan B if the DUP did not agree to return to the executive.

She said: “We have been let down on this many times before and the sense of stagnation and frustration in Northern Ireland is like nothing I’ve ever experienced before.

“I just think belief in devolution and the sustainability of the region is ebbing by the day.

“People need to understand what is the plan B if the DUP don’t or won’t proceed and take seriously their responsibilities to the people of Northern Ireland.

“At what point would you intervene to create an alternative process to meet the basic needs of the people of Northern Ireland and to stop public services and public faith in politics degrading even further?”

Mr Heaton Harris said: “I am not keen on talking about a plan B, because it almost means you have given up on plan A and I will never give up on trying to get the executive up and running.

“But at some point there does have to be an evolution, we have to make sure the Northern Ireland civil service is comfortable and has got the powers it requires for the decisions it is taking.”

He added: “There are some decisions we all know that the Northern Ireland civil service would like ministers to decide on.

“I do not have the power to do that and should I take that power that would put us into a very different position, some might say that is akin to direct rule.”

Ms Hanna asked if there was any scenario in which he would intervene to amend standing orders at Stormont over vetoes by parties blocking the operation of the devolved powersharing institutions.

Mr Heaton-Harris said: “The general principle of consent is the DNA and the skeleton of a very important agreement that has brought peace to Northern Ireland over the last 25 years and changes to it best come from elected members from Northern Ireland.

“I would not be keen to tread into that territory lightly in any way, shape or form.”

Mr Hoare said there had to come a point where the Government was prepared to intervene to the “clamour of despair” from people in Northern Ireland for the return of Stormont.

Mr Heaton-Harris said the obvious route for people to demonstrate their feelings was through the ballot box.

Mr Hoare then asked him if he was giving serious consideration to calling new Assembly elections.

Mr Heaton-Harris said: “I don’t have to have that conversation or thought process for a couple of months yet.

“I have been well advised that testing the public mood through the ballot box only polarises positions in Northern Ireland at this point.”