A bill to legalise euthanasia for the terminally ill fell at the House of Lords, but the widower of Diane Pretty has continued her campaign.
The late Diane Pretty fought a long court battle for an assisted death
Mrs Pretty fought not only her terminal motor neurone disease but also for the right for her husband to assist her to die,before she died in a hospice in May
Mr Brian Pretty told BBC News he will continue "to the end" to fight for assisted suicide to be legalised.
The Assisted Dying for the Terminally Ill Bill was rejected on 12 May 2006.
The private members bill, introduced by Lord Joffe, was defeated on its second reading - the day after the 4th anniversary of Mrs Pretty's death.
The bill would give doctors the right to prescribe drugs that a terminally ill patient in severe pain could use to end their own life, but concerns were raised that doctors could administer lethal drugs.
Lord Joffe pledged to reintroduce the bill at a later date.
Mrs Pretty took her fight for the right to die to the European Court of Human Rights.
Mr Pretty said: "After Diane died it just seemed the right thing to continue trying to change the law.
"I will never forget the suffering Diane went through, or the thousands of messages of support she received from people just like her all over the country who were desperately hoping she would succeed."
Mr Pretty described the Bill as "Diane's Legacy".
He added: "I'll carry on fighting for Diane. Come what may I'll see it through to the end."
Neither euthanasia nor assisted suicide is an option in the UK, where deliberate assistance in death can lead to murder charges.
But in The Netherlands, Belgium and Switzerland, voluntary euthanasia is a legally acceptable option under special circumstances.
Many Britons have travelled to such countries where assisted suicide can be performed by non-physicians.
Campaign group Dignity in Dying has said its newest figures show 76 Britons have gone to the Dignatas clinic in Switzerland for an assisted death.
Deborah Annetts, chief executive of Dignity in Dying, said: "Nobody has done more for the campaign to legalise assisted dying in this country than Diane Pretty.
"The Assisted Dying for the Terminally Ill Bill came about as a direct response to Diane's articulation of the suffering that the law brought upon her and so many others like her.
"Diane's legacy will only be fulfilled when terminally ill, mentally competent people like her can have what she was denied: the choice of a dignified death at the time and place of their choosing."
A study by Brunel University last year showed UK doctors remained more cautious about ending lives than their European counterparts, with most only likely to help if a patent was in the last week of life.
The ProLife Alliance remains opposed to the bill, which it sees as "changing the law for their alleged benefit at the expense of frightening many thousands of vulnerable disabled or ill people."
Julia Millington, political director of the ProLife Alliance, said: "The results of the study fly in the face of deceptive claims made over the last two years by the pro-euthanasia lobby who allege that doctors are killing thousands of terminally ill patients every year in the UK."