RELATIVES should not be allowed to overrule dead loved ones' wishes to become organ donors, a leading medical ethicist has claimed.

Research has revealed one in 10 families of dead patients on the donor register still refuse to give their consent.

But Dr David Shaw, honorary lecturer at Aberdeen University's applied health sciences division and a lecturer in medical ethics at Glasgow University, said respecting such a veto is "unethical, unprofessional and against the spirit of the law."

It has recently been suggested patients should be kept alive using elective ventilation to facilitate the harvesting of organs for donation.

Mr Shaw said ensuring doctors respected the wishes of the deceased is a much simpler way to increase the number of donated organs.

Writing online in the British Medical Journal, he said veto by the family is the main impediment to an increase in organ donation – with at least 10% of families refusing to donate.

The wishes of the family in these cases are upheld and the organs are not removed.

Mr Shaw said families have no legal grounds for overriding the dead person's wishes if they clearly wanted to donate, for example by carrying an organ donor card. He claimed doctors who heed the veto "are complicit in a family denying a loved one's last chance to affect the world".

Mr Shaw said giving in to the family "is unprofessional and lets down the patient and potential recipients of the organs".

The family cannot be blamed for refusing to allow donation under such stress and most doctors are reluctant to add to a family's suffering, he wrote.

However, he added that doctors had "obligations to respect the wishes of the dead patient and to promote the health of the public."

Mr Shaw argued that doctors should not only consider the family of the potential donor but also the families "of those who will die as a consequence of not receiving the donor's organs".

Earlier this year, it emerged the number of people in Scotland signed up to the donor register had reached a record high of more than two million. As of the end of March, 2.03 million Scots were registered organ donors, which amounts to almost 40% of the population compared to 30% for the UK overall.

However, 600 people in Scotland are still awaiting life-saving transplants and last year 36 patients died waiting for an organ to become available.

There has been support for increasing the number of donor organs through a move to a system of presumed consent – whereby anyone not wishing to donate their organs after death would have to opt out of the register instead of opting in.

The British Medical Association (BMA) Scotland is in favour of a "soft opt out" approach that would mean family members would be consulted on the wishes of dead relatives, but the default position would be that Scots have to register a preference not to donate organs.

Scottish Health Secretary Nicola Sturgeon said she is "increasingly sympathetic" to considering a change in the law, with delegates at the SNP conference backing a resolution calling on Holyrood to follow Wales's lead and consider an opt-out system of presumed consent.

The Welsh Assembly has passed legislation to switch to an opt-out system by 2015.