A retired lecturer who is paralysed from the neck down by progressive motor neurone disease should be able to preserve his dignity by choosing the time of his death, the supreme court has been told.

In an emergency appeal for permission to bring Noel Conway’s case before the UK’s highest court, his lawyers argued the 1961 Suicide Act, which criminalises anyone assisting a death, is incompatible with his human rights.

Three justices – Lady Hale, the supreme court president, Lord Reed, the deputy president, and Lord Kerr – are considering whether to hold a full hearing into the right-to-die case after the court of appeal rejected his request on the grounds that it was an issue for parliament. The supreme court is expected to give its decision in the coming days.

At the hour-long hearing on Thursday, the court was told another tetraplegic patient, Paul Lamb, who has been paralysed below his neck since a car accident nearly 30 years ago, is seeking to join his application to the supreme court.

David Pannick QC, representing Conway, told the court: “This is a question of whether it’s a breach of his human rights to impose a blanket ban [on assisting death] … Noel Conway contends that because of the need to respect autonomy and dignity, [the government] must show compelling justification for preventing someone with full mental capacity from receiving assistance to end their life. He recognises there’s a balance to be struck in the need to protect the vulnerable.”

If someone with full mental capacity had a settled view, made an informed decision and was expected to live for less than six months, Lord Pannick said, they should be allowed to receive assistance to die. The concept of a terminally ill patient expected to die within six months already exists in section 82 of the 2012 Welfare Reform Act, he pointed out.

The government has argued modern palliative care allows some patients to die if they withdraw from artificial ventilation that is keeping them alive. But Pannick said such a death “could last only a few minutes, but in some cases hours, and other cases days”. It would induce a “drowning sensation” and would not constitute a dignified end, he added.

Sir James Eadie QC for the Ministry of Justice told the court Conway remained on ventilation 23 hours a day. Advances in palliative care could help those on ventilation to end their lives, he said.

The decision on whether section two of the Suicide Act was compatible with human rights was a matter for parliament, not the courts, Eadie added. Parliament has repeatedly considered the issue and decided not the change the law.

“A significant preponderance of medical opinion is against these proposed changes to the act,” he said, adding that the UK was not out of line with regulations in most other European countries. “There’s only two or three countries that permit assistance in some respect,” Eadie said.

Before the hearing, Yogi Amin, a solicitor with the law firm Irwin Mitchell, who also represents Conway, said: “He’s still eating and drinking and thinks he has a good quality of life, but he wants to have control and have a choice at the end.”

Humanists UK is seeking to intervene in the case if the supreme court grants permission to appeal. The organisation’s chief executive, Andrew Copson, said: “Noel hopes to establish that all people who are terminally ill must be able to make their own choices about how they want to die and to have these choices protected by law. We are proud to support Noel’s case.

“In any assisted dying law there must be strict legal safeguards in place, but being able to die, with dignity, in a manner of our choosing, must be understood to be a fundamental human right.”

Nancy Collins, a partner at the law firm Hodge Jones & Allen, which represents Humanists UK, said: “We hope the supreme court will make a positive finding in support of Mr Conway and the proposed scheme for assisted dying so that terminally ill people are able to choose how and when to die, where they wish to do so. We believe that this is a fundamental right that should now be recognised and protected by the law.”

However, Dr Peter Saunders, the campaign director of Care Not Killing, said: “We hope the supreme court will recognise that the safest law is the one we have – a complete ban on assisted suicide and euthanasia. Importantly, our laws treat everyone the same regardless of their age or disability, deterring the exploitation, abuse and coercion of vulnerable people. As we have seen in the US states of Oregon and Washington, fear of becoming a financial or care burden is cited by more than half of those choosing to end their lives.

“Worryingly, it is not just in the US where we have seen disturbing developments, once safeguards have been removed. In Holland and Belgium, a law introduced to alleviative the suffering of mentally competent adults is routinely used on non-mentally competent adults and even children. This why in this area the blanket ban is the right approach and we hope the supreme court will reaffirm this.”