A man who feels "entombed" by a terminal illness has taken his "fight for choice at the end of life" to the High Court.
Noel Conway, a 67-year-old grandfather and retired lecturer, is challenging the current law on assisted dying.
Mr Conway, from Shrewsbury, was diagnosed with motor neurone disease in November 2014 and is not expected to live beyond 12 months.
He is reliant for 20 hours each day on a non-invasive ventilation device and was not well enough to be at the hearing in London on Monday, although he hopes to attend by video link on Wednesday.
When he has less than six months to live and retains the mental capacity to make the decision, he wishes to be able to enlist assistance from the medical profession to bring about a "peaceful and dignified" death.
The law as it stands means that anyone who helped him would be committing a criminal offence.
He wants a declaration that the Suicide Act 1961 is incompatible with Article 8 of the European Convention on Human Rights, which relates to respect for private and family life, and Article 14, which protects from discrimination.
Richard Gordon QC, told Lord Justice Sales, Mrs Justice Whipple and Mr Justice Garnham that Mr Conway had expressed graphically the effect of his illness upon him, referring to the feeling of "entombment".
He said others in Mr Conway's position might consider making arrangements to fly to Switzerland to go to Dignitas to die far from home - and expose anyone who helped with the arrangements to a risk of prosecution.
But he did not see that as an option. Nor did he consider that he could take the step of either himself removing the ventilation device or asking another to do so.
"The choices facing the claimant are therefore stark and unpalatable: seek to bring about his own death now whilst he is physically able to do so but before he is ready to do so; or await death with no control over when and how it comes."
Mr Conway, who is supported by Dignity In Dying, has already been to the Court of Appeal to win the right for what he calls his "fight for choice at the end of life" to proceed.
The case is opposed by the Secretary of State for Justice, with Humanists UK, Care Not Killing and Not Dead Yet UK also making submissions.
A ruling is not expected until the autumn.
It is the first challenge to the existing law since the case of Tony Nicklinson, who suffered from paralysis after a stroke.
That was ultimately dismissed in June 2014 by the Supreme Court, which said it was important that Parliament debated the issues before any decision was made by the courts.
After debates in the House of Commons and the House of Lords, Parliament decided, at least for the moment, not to provide for legislative exceptions to the 1961 Act.
Mr Gordon said it was a "very narrowly focused" case which sought only to challenge the blanket ban on assisted dying for a relatively small category, which included Mr Conway.
This covered adults over 18 who were diagnosed with a terminal illness with a prognosis of six months or less, who had mental capacity, who had made a "voluntary, clear, settled and informed" decision to receive assistance to die, and who retained the ability to undertake the final act required to bring about their death.
He said: "Inevitably, the question of assisted dying is one that provokes a strong, often instinctive, emotional response.
"However ... the substantive issue engaged here ... involves law and not morality.
"It is founded solely on the evidence before the court and on a comparison of the current law on assisted dying with the law in other related areas."
Mr Gordon said the evidence demonstrated that a practical scheme, including suitable safeguards, could be devised for those in Mr Conway's narrowly defined group who could safely be provided with assistance to die without affecting the legitimate aim of the protection of the weak and vulnerable.
Mr Conway's primary goal was to obtain a recognition that, as a matter of law, the current ban could not be justified in respect of him and the identified category.
Counsel said: "It would be for Parliament to respond in due course to such a declaration, and for its consideration of the wider moral and ethical issues raised to be informed and guided by that recognition."
Before the hearing, campaigners from both sides of the debate spoke out.
Lord Low of Dalston, the crossbench peer who is blind and a lifelong campaigner for the rights of disabled people, described fears expressed by Not Dead Yet UK as "groundless".
"Mr Conway's case is not based on the argument that disabled people are a burden - just that he should have the right of choice at the end of life in face of unbearable suffering.
"It is ironic that people who campaign so vehemently for disabled people to be given choice in every other aspect of their lives should seek to deny choice to a fellow disabled person over the time and manner in which he ends his own life.
"If Mr Conway were granted the right he is seeking, it would have no implication for other disabled people, other than that they too would have the right to choose the time and manner of their death.
"No-one would be compelled to avail themselves of this right if they did not wish to do so."
Not Dead Yet UK, which opposes attempts to legalise assisted suicide for disabled and terminally ill people, said it recognised and empathised with Mr Conway's fears for his future but could not support his action.
Baroness Campbell of Surbiton, one of its founders, said: "We have successfully seen off attempts to change the law on assisted suicide in Parliament.
"Now we must change tactics to ensure the courts continue to uphold our equal right to life.
"The law must not be weakened via the back door."
Co-founder Phil Friend said: "A change in the law is a terrifying prospect to the vast majority of disabled and terminally ill people who work hard towards achieving equality for all.
"Until we have reached that objective, assisted suicide will remain a dangerous and prejudiced option, likely to increase suffering and distress".
The hearing was adjourned until tomorrow.