By Emma Wilkinson
Health reporter, BBC News
Some countries permit assisted dying, but the UK does not
Former health minister Lord Warner has backed calls for a law change to allow assisted death for terminally-ill patients who want to die.
Dignity in Dying is pressing the government to legalise assisted death in mentally competent patients.
The campaign group has also called for more resources for palliative care and "end of life" care plans.
The British Medical Association said it was opposed to doctors helping patients to die.
Lord Warner spoke to the BBC as Dignity in Dying published their charter for end of life care.
In addition to allowing terminally-ill, mentally competent patients control over their death, the charter calls for "end of life" plans for all patients, increased awareness of the right to refuse treatment and better resources for palliative care.
Lord Warner said: "A terminally-ill person who is mentally competent should have the right to choose an assisted death."
"This charter is all about enabling people to exercise personal choice, and one part of that - for a minority of terminally-ill people - is when things get absolutely too much, their pain threshold has been breached and their quality of life is very poor, having the choice of an assisted death."
"We would like to see the government responding to all points in this charter."
Last May, the House of Lords blocked a bill which would allow terminally ill people to be helped to die.
Current laws prohibit any form of assisted dying.
Dignity in Dying estimates that over the past decade, 90 Britons have chosen to travel to Swiss clinic, Dignitas, in order to end their life.
A spokesperson for the British Medical Association said: "The BMA has members with wide ranging views on these issues, but at last year's annual meeting the majority of doctors voted to oppose any form of assisted dying."
John Wiles, a consultant in palliative medicine and member of the Care Not Killing Alliance, said he would support Dignity in Dying's call for better palliative care but not for a change in the law on assisted dying.
"I've looked after many patients who know they will die from their disease and although they express a wish to die at a particular time, they will quite often change their minds.
"We don't think that giving people the choice to die is part of palliative care."
A spokesperson for the Department of Health said they were due to publish an End of Life strategy in July, but this would not cover assisted death.
She added there had been a number of private members bills on assisted dying in recent years and the governments' position had been to remain neutral.