Legal action brought by locked-in syndrome sufferer Tony Nicklinson, who wants a doctor to be able to end his "intolerable" life lawfully, can go ahead following a judge's ruling today.
The decision was announced at the High Court in London by Mr Justice Charles, who had been asked to decide on a preliminary "strike out" application in the case made by the Ministry of Justice.
He had heard argument that it was not for the courts to act, but Parliament.
Announcing his decision today the judge allowed most of Mr Nicklinson's case to proceed - striking out one part of his claim.
Mr Nicklinson, 57, who is married with two grown-up daughters and lives in Melksham, Wiltshire, wants a doctor to be "lawfully" able to end his life, which he sums up as "dull, miserable, demeaning, undignified and intolerable".
He launched a legal action seeking court declarations that a doctor could intervene to end his "indignity" and have a "common law defence of necessity" against any murder charge.
At a recent hearing, Paul Bowen, for Mr Nicklinson - who suffered a stroke in 2005 - said the Ministry of Justice had not advanced any arguments which were a sufficient "knock-out blow" to justify striking out the action.
The judge gave Mr Nicklinson the go-ahead to take his case further in judicial review proceedings in relation to two of three declarations sought.
He ruled that Mr Nicklinson "has established an arguable case in support of the declaration he seeks relating to the availability of a defence of necessity".
He added: "Accordingly, I shall not strike out that part of his claim, and so far as it is necessary for me to do so, I give permission for him to seek such relief by way of judicial review".
When the case goes to a full hearing Mr Nicklinson will be seeking a declaration that "it would not be unlawful, on the grounds of necessity, for Mr Nicklinson's GP, or another doctor, to terminate or assist the termination of Mr Nicklinson's life".
Mr Justice Charles also gave the green light in relation to a second declaration sought by Mr Nicklinson over his right to respect for private life under Article 8 of the Human Rights Convention.
He said he had concluded that Mr Nicklinson "has established an arguable case in support of the declaration he seeks in respect of Article 8" and would therefore not be striking out that part of his action.
The declaration sought is that the "current law of murder and/or of assisted suicide is incompatible with Mr Nicklinson's right to respect for private life under Article 8...in so far as it criminalises voluntary active euthanasia and/or assisted suicide".
But the judge struck out his case in relation to a third declaration.
That declaration was that "existing domestic law and practice fail adequately to regulate the practice of active euthanasia, both voluntary and involuntary", in breach of Article 2 - the right to life.
Mr Justice Charles said in his judgment Mr Nicklinson did not have any realistic chance of persuading a court to grant that declaration "even if it is assumed that his underlying arguments based on the position of others are arguable".
He explained:" The reason for this is that the court should not engage in that debate because it is a matter for Parliament."
The judge said: "The crucial distinction between this conclusion in respect of the third declaration and my conclusions in respect of the first two declarations sought is the point that, in support of the first two, the claimant is advancing an argument based on his asserted rights."