Lawyers representing the parents of Archie Battersbee have told Court of Appeal judges that, unless the withdrawal of his life-sustaining treatment is postponed, the court will be “complicit” in a “flagrant breach of international law”.

Hollie Dance and Paul Battersbee made a last-ditch application to the United Nations (UN) Committee on the Rights of Persons with Disabilities last week after their court battle against Barts Health NHS Trust over his treatment ended.

The youngster was due to have his life-support at the Royal London Hospital in east London ended at 2pm on Monday, after a High Court judge ruled this to be in his best interests and the family exhausted all routes of appeal.

However, the UN committee issued a request to the UK Government on Friday, asking that it “refrain from withdrawing life-preserving medical treatment, including mechanical ventilation and artificial nutrition and hydration” from Archie while his case is under consideration.

The Government’s legal department then wrote an urgent letter on Sunday on behalf of Health Secretary Steve Barclay, asking the courts to urgently consider the committee’s request.

The Court of Appeal began considering the issues at a hearing on Monday and is due to give a ruling not before 3pm.

The trust will not take any steps to end Archie’s treatment until the court has given its decision on the latest development.

In written submissions to the court, Edward Devereux QC, acting for Ms Dance and Mr Battersbee, said the committee’s request is “binding” under international law.

He argued that any failure to abide by the committee’s request, made in accordance with the UN Convention on the Rights of People with Disabilities which was signed and ratified by the UK in 2008 and 2009, would amount to a “flagrant, egregious and unacceptable breach of international law”.

Mr Devereux asked the court to grant a stay to prevent the withdrawal of life-sustaining treatment until after the committee has had time to consider Archie’s case, but said he did not know how long that would take.

As an alternative, he asked the court to grant a stay within the next week to give time to seek more information from the committee as to the likely timescale for its decision.

He told the court: “What this court is considering now is whether it is going to be complicit in a flagrant breach of international law.”

Mr Devereux also argued that it would be “wholly inappropriate” for the court to reach a decision without the Government being required to provide its views on the committee’s request.

However, Lady Justice King, one of the judges hearing the urgent application, said the Government has chosen not to intervene in the case.

Bruno Quintavalle, also representing Archie’s parents at the hearing, said it is “very unfortunate” that the Government has chosen not to play any part in the proceedings.

However, Fiona Paterson, representing Barts Health NHS Trust, said the Government has chosen “not to make submissions but instead effectively to seek the court’s guidance”.

She told the court there is a “commendable logic” in that decision given that the court has all of the information necessary, having considered the case previously.

She said the UN committee’s request is not binding and added that the matter can be determined by the court and that no further participation of the Government is necessary.

Claire Watson QC, for Archie’s guardian – an independent adviser appointed to represent him – said there has been no change to the guardian’s view that, in light of the youngster’s “parlous” condition, it is no longer in his best interests for treatment to continue.

Ms Watson also said, in written submissions, that there would be no breach of law by refusing the committee’s request, adding: “The UN committee’s request to the UK Government to refrain from withdrawing life-preserving medical treatment is purely a request.

“The request is not enforceable and, if not acceded to, the consequences for the state party would be criticism and moral censure by the UN committee, and potentially wider international criticism for frustrating the function of the committee.”

The trust wrote to the family over the weekend to inform them it intended to end treatment on Monday afternoon, but the Government then referred the UN’s request to the court for “urgent consideration” on Sunday.

In its letter, the UN committee said it had “requested the state party to refrain from withdrawing life-preserving medical treatment, including mechanical ventilation and artificial nutrition and hydration” from Archie while his case was under its consideration.

Ms Dance said the family felt “relieved” that the Government had taken the UN’s intervention seriously.

She said: “The anxiety of being told that Archie’s life-support will be removed tomorrow at 2pm has been horrific.

“We are already broken and the not knowing what was going to happen next is excruciating.”

Archie’s parents are being supported by campaign organisation the Christian Legal Centre.

The trust previously said in a letter to Ms Dance and Mr Battersbee, who are separated but both live in Southend, Essex, that the withdrawal process will aim to “preserve Archie’s dignity”.

The trust said in the letter: “We understand that any discussions around the withdrawal of Archie’s treatment are very difficult and painful.

“However, we want to ensure that you and your family are involved as much as you wish to be.”

It added: “You or any of the family may wish to lie on Archie’s bed with him or have him in your arms, if that should be practically possible.”

Ms Dance said this would amount to “extraordinary cruelty” and a “flagrant breach of Archie’s rights as a disabled person”.

She said: “Archie is entitled to have the decisions about his life and death, taken by the NHS and UK courts, to be scrutinised by an international human rights body.

“Hastening his death to prevent that would be completely unacceptable.”

Judges heard that Ms Dance found Archie unconscious with a ligature over his head on April 7, after she believes he took part in an online challenge.

Doctors believe Archie is brain-stem dead and say continued life-support treatment is not in his best interests.

A spokesman for the Department of Health and Social Care said: “We recognise this is an exceptionally difficult time for Archie Battersbee’s family and our thoughts are with them.

“The Government asked the High Court to urgently consider the request from the UN Committee on the Rights of Persons with Disabilities.”