PLANS for an opt-out organ donation system in Scotland will throw up more questions around consent and families' right to veto, one of Scotland's leading experts on medico-legal ethics has said.

Professor Alison Britton said the terminology being used in the new legislation is confusing and that there is a risk that relatives will be more likely to refuse permission for their loved ones organs to be used in transplant unless the law is accompanied by a major "cultural change".

Britton, a professor of healthcare and medical law at Glasgow Caledonian University who recently chaired the review into mesh implants, said role of the next of kin in the process "remains an anomaly".

She said: "In the current legislation, the role of the family remains curiously silent and what we rely on is custom and practice, and it looks like that will continue in the proposed legislation.

"So at the moment even if the donor has made this active step of saying 'yes, that is my intention', if the families say 'no, we don't want that to happen' - for cultural and religious reasons, lack of understanding, they feel the patient has suffered enough, they don't like the idea.

"The reality is no one is going to fly in the face of that."

A record 52% of Scotland's population is signed up to the donor list, but the plan will make all adults in Scotland organ donors by default - unless they take the choice to opt-out.

A third option to actively 'opt-in' will also remain available.

However, Britton said the language in the Human Tissue (Authorisation) (Scotland) Bill is wrongly attributing "consent" to the relatives, and "presumed authorisation" to the deceased unless they had actively opt-out of the donor list during their life.

"The terms are a bit misleading," said Britton. "It should be 'presumed consent', and the authorisation or permission is something that the families take a role in.

"For me 'authorisation' is a bit like signing your children's school trip form. But consent is something that has more weight, more value, more meaning.

"To consent to something demonstrates an understanding, that it's something you're thought about. To me, the two are not interchangeable."

Britton said that existing case law also highlights that the next of kin have a human right to be consulted under an opt-out system, pointing to the case of a bereaved wife from Latvia who took her case to the European Court of Human Rights (ECHR) after medics failed to get her permission to remove tissue from her husband after he had died in a car crash in 2001.

Dzintra Elberte only discovered that tissue had been taken from her husband's legs before his funeral when Latvian police launched a criminal inquiry two years later into the illegal removal of organs and tissue between 1994 and 2003.

It turned out that forensic experts had removed and dispatched some of his body tissue to a pharmaceutical company in Germany to be modified into bio implants.

The prosecution was eventually dropped in 2008 when Latvian judges ruled that while the country's presumed consent system gave next of kin a right to object, the law "did not impose such an obligation". However, Mrs Elberte subsequently took her case to the ECHR where she was awarded €16,000 (£14,000) damages after judges ruled unanimously that her human rights had been violated.

They also criticised "inadequate legal safeguards", which meant that while a deceased's next of kin were allowed to object to organ donation the law "did not clearly define the corresponding obligation of experts to obtain consent".

"There is this aspect of a 'human right to be consulted'," said Britton. "But the opt-out legislation that's been passed in Wales and proposed for Scotland hasn't really gone down the path of defining that. Now perhaps they feel that because that dialogue and that communication is going happen at the time with the families, but the reality is that very often time is of the essence.

"The law would look at a 'reasonable' attempt - whatever that means in law - to get in touch with whoever is available."

The vexed question of whether opt-out will actually increase the number of organs becoming available for transplant is something we "cannot answer", said Britton. Partly it is because very few people - around one per cent - die in circumstances, such as road accidents, where organs would be viable.

In Wales, where an opt-out system came into effect in 2015, there was little change in the number of organ donors: figures show there were 101 deceased donors in the 21 months before the law changed, and 104 in 21 months after.

Britton stressed that a change of legislation alone on its own will not be enough - something she acknowledges that MSPs have taken on board.

In Spain, where opt-out was introduced in 1979, there was little discernible effect until a decade later when funds were poured into training more doctors and nurses for intensive care. The whole ethos of the country is also geared to organ donation as a norm, said Britton. But, she stressed, this is something that Scotland - with its comparatively high donor registration rates at present - is well-placed to mirror in future.

She said: "Scotland sadly doesn't have the luxury of the number of intensive care units that Spain has. The other difference is that where we talk about opt-in, opt-out and presumed consent, Spain doesn't tend to emphasise so much on the opt-out element.

"They emphasise much more that there is a general cultural understanding that 'everybody opts in', but they still have discussion with the family as well.

"Scotland actually has a very good record in terms of the size of the country and population we have. There is good uptake of people currently opting in.

"So even if it doesn't make a difference in the short term, looking at the experience of other jurisdictions in the longer term, it does."