Bradie is an organ donor transplant coordinator at one of Scotland's busiest hospitals, at the centre of the most morally contentious issue confronting the NHS.

Last weekend, Prime Minister Gordon Brown put organ donation at the forefront of Britain's political debate. He announced his personal support for 'presumed consent' for organ donation as a way of increasing the number of life-saving transplants for critically ill patients. In Scotland, the SNP Government echoed his sentiments.

If, as is now expected, there is to be a change in the law north and south of the border, the UK will operate an opt-out system where everyone is considered an organ donor unless they specifically object. It's a revolution that Scotland on Sunday has been campaigning for since July.

Brown's comments have forced the public to examine the practical implications for organ donation, and to look at the moral quandaries that exist in deciding to use the organs of one dead or dying human being to save the life of another. And at the heart of these questions is the work of Scotland's 15 full-time transplant co- ordinators, whose numbers will soon be added to under a plan unveiled last week by the Scottish Government.

So what does Bradie's job involve and what questions does it throw up for herself, the bereaved families she has to face and for NHS staff at the sharp end of critical patient care? And what does her experience tell us about the debate that is rapidly gathering pace on presumed consent that will have implications for us all?

Bradie is usually sifting through paperwork in her tiny, windowless cubbyhole of an office on the second floor of the Royal Infirmary of Edinburgh when her beeper goes.

This is the call from a local intensive care unit where a patient has died, and it will trigger an 18-hour chain of events. It's simply another long working day for Bradie but one that will dramatically change the lives of several families.

Typically, a patient at a nearby intensive care unit in Lothian, Borders or Fife, who has been in a car accident, has suffered brain injuries so horrific that attempts to save their life are futile. They may have been in hospital for 24 hours or a few days.

At this stage, the patient will be on a ventilator but their family will have been informed that he or she is brain-stem dead, usually from a cerebral bleed. Two separate tests are performed to confirm this. Bradie is then called in by the patient's doctor to lead the delicate, sometimes lengthy discussion with the family on donating their loved one's organs.

First she checks to see if the patient has registered their wishes on the Organ Donor Register. But even if they have not, she will approach the family nonetheless.

Bradie, a senior nurse with a 20-year background in transplantation, says: "You are dealing with the acutely bereaved and you don't know what you are going to face because everyone's reaction to grief is different. But we work with the intensive care team to support the family.

"I am just there to offer something to them. They can say yes or no. I am there to support and guide the family through that process and to benefit other patients. It's not easy at all but it's all about the family. From there we hope that we can do something that helps them as well."

The issue of organ donation is not broached until the medical team is sure that the family fully appreciates that their loved one has died. Sometimes the family bring up the subject of organ donation themselves. Otherwise, it is up to doctors and transplant co-ordinators. Because of the need for haste and the high stakes in lives that could be saved, her methods can at first seem uncompromisingly direct.

"We all undergo training in how to approach families," she says. "We explain that if they are on the Organ Donor Register, then this is what they would have wanted. We are carrying out their last wishes.

"If they are not on the register, we establish if the family know their wishes. They often say that the person was a caring individual and the family believes it is what they would have wanted.

"If they don't know what the wishes were and can't make that decision, or even if they say no, I would still enquire why to make sure it's not about misconceptions, to make sure they are informed and have the chance to correct that misconception."

Once a decision has been made, the family must answer a series of questions on the patient's health, medication and sexual behaviour to establish how healthy the organs are likely to be. Time is of the essence, so these deeply personal and sensitive questions must be asked there and then.

Meanwhile, tests are performed on the patient's body and a call is made to UK Transplant, the central body dealing with organ transplants, to establish the current 'allocation run' of patients in need of the organs available across the UK and locally. Once this is known, Bradie rings the relevant hospitals to let them know they must alert their patient that an organ has been found. She then organises a 'surgical retrieval team' to come to take the organs.

While family members come to terms with their loss, other families – whose loved ones have life-threatening medical conditions ranging from heart disease to liver failure – allow themselves some hope. Medical teams in several hospitals spring into action to begin the gruelling task of retrieving organs and uniting them with their new recipients. Bradie is present during the six-hour retrieval operation to coordinate proceedings. Good timing and transport plans are essential. She explains: "It's very busy in the operating theatre with calls from the receiving teams making sure everything is going to the planned time and that the organs are okay.

"Simultaneously, patients are being brought into their own local centres for their organ transplants. Heart and lung patients must receive organs within four hours. Sometimes the patient will be in theatre waiting if it is a very urgent operation. Phone calls are going back and forward to get the patients anaesthetised.

"Speed is of the essence with hearts and lungs, but we have got ways of getting them moving. It can be blue-lighted from the donor hospital to a private jet to London or Birmingham, wherever it is needed. Most other organs such as liver and kidneys go on scheduled flights. They go through security and are taken up to sit by the pilot. I have had phone calls from pilots just telling me everything is all right."

After the transplant operations have taken place, Bradie will write to the grieving family to let them know how their loved one's organs have been used. They are not given recipients' names but basic information, such as gender and age. "We sometimes pass letters on from recipients but we keep it all anonymous," she says. "Our recipients are aware that some family is in great distress at that time, and that for their happiness there is a great sadness for another family."

There is undoubtedly a ghoulish aspect to her job but the force that drives Bradie is the belief that she is carrying out the last wishes of the deceased. She says: "You are drawn to areas in nursing that suit you best. I hope I can offer something to the people I care for and I find it a hugely rewarding job. I firmly believe in transplantation as a treatment option and that comes from the generosity of someone putting their name on the register."

But political will has now moved to back a system that will regard everyone as being an organ donor unless they make a formal objection in their lifetime. Even among transplant staff, this is a controversial move.

Laura Buist, a transplant surgeon and director of renal transplants at the Western Infirmary Glasgow, points out just how low Scotland's transplantation rates are in comparison with Spain, which has presumed consent and has invested hugely in transplant support services.

Buist says a shift to presumed consent might be the only way to increase donor numbers. But, perhaps surprisingly, she is not an enthusiastic supporter of such a move.

"Presumed consent is on the horizon," she says. "I am sitting on the fence a bit. Sometimes I think organ donation should be altruistic, but when it's blatantly obvious that people don't want to help their fellow man, then the time may have come to go for presumed consent.

"We need a re-education of the whole population that donation is a good thing and that your organs will be used after you die. If presumed consent is the way to go, then I am happy with that."

Bradie is also willing to go along with any legal changes to her job. In the cases where the person has made their wishes clear, it would make little difference, she says. But it could make a difference to how she approaches families who are unwilling. "I welcome the presumed consent debate and if that is what people want, it is what we should be doing," she says.

"I will go with what the general public want. However, I believe it needs more than that to raise donor numbers. The easiest way is to know what the person's wishes were. That's the thing that makes organ donation easier for every family."