I became a blood donor in 1976 during my first term as an undergraduate student; it was the first donor session I was old enough to attend. I gave regularly and then lapsed for various – largely legitimate – reasons: I travelled extensively through Asia; I had invasive procedures and surgery; I had acupuncture and ear-piercing; I had more surgery; I had a tattoo, all of which meant at various times I was unable to donate.

I returned when I could; I failed health screens due to anaemia a few times, but I’m now back in the rhythm of regular donation. Part of my motivation is that my Dad – who died three years ago – had a rare blood disorder (MDS – myelodysplasia syndrome) which meant that for several years he was transfusion dependent. In his last 18 months he was receiving three or four units every few weeks. I became obsessed with charting his units, and his results; plotting his haemoglobin and white cell counts against his transfusion dates on a graph in a futile attempt to keep control of a situation in which we were powerless, and realising the inevitable downward trend.

Things have changed with donation since I started giving – there are now much more sophisticated reclining chair-beds; computerised records, and automated thank you texts from the donation centre following giving, and another following up telling you when your blood has been issued and to which hospital. I like that, it makes me feel I’m achieving something of value. So why do I feel so uneasy about the Conservative proposal (almost unnoticed in the disastrous conference speech from Theresa May) to introduce an opt-out on organ donation, where consent will be presumed unless you have indicated to the contrary? What is currently at the heart of blood and organ donation in England is its voluntary nature; this is what Richard Titmuss famously described as ‘The Gift Relationship’, founded totally on altruism and philanthropy. I donate blood because I want to; a bit of me feels that I ought to, making some regular deposits in exchange for all the withdrawals we’ve made, but I’m not obliged to do so. I don’t get a summons in the post requiring my attendance, or showing my balance sheet of how much blood I still owe. And if I did, I imagine I would feel less warm and satisfied about donating; indeed, probably quite resentful.

Presumed consent is a strange concept, and not one that would find favour in any other walk of life – imagine it in relation to sex, or to charitable donations. The idea that something as personal as bits of your body might actually be taken without consent because it is assumed you wouldn’t mind, raises enormous ethical issues.

Organ donation is of great importance in enabling life-saving treatment and some semblance of normal life, particularly in renal failure, but – as with blood – ‘the gift of life after death’ is surely a private and personal matter? Some other countries have already adopted the presumption of consent, including other parts of the United Kingdom, but the evidence on whether it is successful is equivocal at best. The argument for opting out is that it would increase the supply of organs and save additional lives, but in Wales (which introduced an opt-out in 2015) there appears to have been a decrease. It also makes arrangements more complex, with opt-in donors, opt-out refusers, and deemed consent groups co-existing in the population. The Welsh model is described as a ‘soft opt-out’ which is not intended to be legally enforced, which raises the question of why legislate for it in the first place? If this is more about raising awareness of the value of organ donation, and supporting donors to opt-in, there may be other more effective ways to do that.

Neither would an opt-out system avoid the need for difficult conversations with bereaved families, and it could actually make those much more difficult. It is one thing to ask relatives if they would consider donating the organs of a loved one, but quite another to tell them that they have little or no choice in the matter. What happens to trust between doctors and patients, and their relatives? At what point might people worry about secondary gain, and that they or their relative are viewed less as a patient and more as a donor awaiting organ harvesting, and what impact might that have on the treatment and care they receive?

The adoption of an opt-out system in England is to be the subject of consultation, but the issues are complex and multi-faceted. The Department of Health will seek views on:

• How government can increase rates of organ donation, particularly from BAME communities where consent rates are low.

• How the issue of consent should be managed within the NHS.

• What role technology could play in helping people discuss their preferences with their families.

• How opt-out would work in practice, what safeguards would be necessary, and how families could be supported.

International experience is mixed, and there are difficulties in comparing models, but Shepherd et al’s analysis of opt-in and opt-out systems across 48 countries is illuminating and suggests that “opt-out consent may lead to an increase in deceased donation, but a reduction in living donation rates.” Furthermore, there are examples of countries (notably France and Brazil) where opt-out systems have decreased donations, which is “partly attributed to increased levels of mistrust towards medical professionals.”

In 2008 the UK Organ Donation Taskforce concluded that opt-out consent should not be introduced, although on their recommendation clinical leads for organ donation have been appointed in each hospital trust, with positive impact on opt-in donations. As Shepherd et al comment, the issue of adopting an opt-out model “is an area where opinion is strong and evidence is weak”. Neither is a good foundation for policy making.