The Good Friday Agreement is not up for negotiation as part of Brexit, according to the Taoiseach Leo Varadkar.

DUP leader Arlene Foster has suggested the agreement is not untouchable - and could be altered to end the Brexit deadlock.

In an interview with the UK Telegraph, Ms Foster claimed the Irish peace deal was not a "sacrosanct piece of legislation."

"It has been deeply frustrating to hear people who voted remain and in Europe talk about Northern Ireland as though we can’t touch the Belfast Agreement," she said.

"Things evolve, even in the EU context."

She claimed it was a "misinterpretation" to hold the peace agreement up as sacrosanct.

She has been accused of being reckless with the peace process for making the comments.

Mr Varadkar says it is something the Government will not consider.

"It could only be changed with the agreement of the British and Irish Government, and could only be changed with the consent of the people of Northern Ireland - and indeed cross--community consent at that.

"It is not something that can be changed by any one political party or by any one government.

"And certainly as far as this Government is concerned, the Good Friday Agreement is not up for negotiation in these talks over Brexit".

"Peace and stability"

Earlier Tánaiste Simon Coveney has warned the DUP leader that she was "wrong" to suggest the Good Friday Agreement could be altered.

In a tweet, Mr Coveney said he has "respect" for Ms Foster, but warned "she is wrong on this."

He said the Good Friday Agreement was voted for by the overwhelming majority of people on both sides of the border.

He said it has "helped to end violence and provided for the most prolonged period of peace and stability in Northern Ireland’s history."

He said the Government would "defend and protect it" throughout the Brexit process.

I have respect for Arlene, but she is wrong on this. GFA was voted for by overwhelming majority in NI & IRL, has helped to end violence + provided for the most prolonged period of peace+stability in NI’s history. We will defend+ protect it through #Brexit. https://t.co/EoZrJC3lGz

— Simon Coveney (@simoncoveney) October 2, 2018

Meanwhile, Sinn Féin President Mary Lou McDonald accused Ms Foster of showing a "reckless disregard for the peace process, prosperity and progress."

"The Irish Government must make clear that the Good Friday Agreement will be protected and remains the basis for stability and progress," she said.

She warned that Ms Foster has "learned nothing" since leaving the Ulster Unionist Party - which supports the Good Friday Agreement - to join the "anti-agreement DUP."

"The Good Friday Agreement was endorsed by the vast majority of people north and south," she said.

"It is the people’s agreement and not a chip to be bargained with as part of any Tory/DUP Brexit deal.

"Brexit is incompatible with the Good Friday Agreement.

"The actions of the DUP and their deal with the Tories is bad for our economy and undermines the rights of citizens." 

Hard border

Meanwhile, UK Prime Minister Theresa May is facing calls to clarify the UK Government’s policy on the border – after UK Chancellor Philip Hammond warned the Conservative Party conference that a ‘no-deal’ outcome was likely to lead to a hard border.

He said the border would have to be compliant with World Trade Organisation (WTO) rules if the UK crashes out without a deal.

"We are depending on the WTO to regulate our relations with the rest of the world, we will have to comply with the rest of WTO regulations or we will find we can't enforce our WTO rights against others," he said.

It is the first time a senior British government minister has admitted a hard border may have to be imposed.

Clarification

Sinn Féin Brexit spokesperson David Cullinane said it is a very worrying development.

"All of the rhetoric that has come from the British Government and the British Prime Minister up to now has been that there will be no border and there will be no inspections or checks at the border," he said.

"That has been made clear time and again by Theresa May.

"So if there is a change in Government policy she needs to say it and she has to come out and be very clear and very honest with people."

Backstop

Meanwhile, reports in the UK this morning indicate that Mrs May’s new proposals on the border will involve the UK remaining tied to EU customs rules for as long as it takes to find a mutually acceptable technological solution can be found.

The Times newspaper reports that Westminster will also accept the need for regulatory checks between Britain and the North if the backstop comes into force.

The EU has previously warned that the backstop cannot be widened to include the whole of the UK.

Confidence and supply

In her Telegraph interview, Ms Foster also backed the "belief" and "spirit" of former UK foreign secretary Boris Johnson’s blueprint for Brexit - and criticised a lack of aspiration for the future among some UK Government ministers.

She said the DUPs confidence and supply arrangement with the Tories is a "party to party" deal that does not rely on Mrs May remaining as leader.

"I think people want that hope, they want to be positive," she said.

"We haven’t been able to talk about the aspirations for the nation; we have spent so much time arguing about what’s happened; is it going to be a disaster for Ireland in inverted commas...instead of actually focusing on what we can achieve in the UK with the Brexit negotiations.

"What we want to see - and I’m not making a comparison between Boris and the Prime Minister - is belief.

"We want to see that spirit."

Additional reporting: Sean Defoe and Jack Quann