Laws governing organ donation and tissue retention are to be overhauled in England, Wales and Northern Ireland.
Laws are changing on Friday
Under the Human Tissue Act, donors will have a legal right to have their wishes followed.
People will also face jail if they remove and store human tissue without consent.
PROFESSOR ALEX MARKHAM, CHIEF EXECUTIVE OF CANCER RESEARCH UK
"Research using human tissue is essential if we are to improve our understanding of cancer and develop more effective cancer treatments.
"Cancer Research UK is hopeful that this new regulatory framework will give researchers the support they need to carry out their work."
DR EVAN HARRIS, LIBERAL DEMOCRAT MP AND CHAIRMAN OF THE ALL PARTY PARLIAMENTARY KIDNEY GROUP
"I strongly welcome the changes to organ donation to ensure that the wishes of the deceased prevail, reducing the power or opportunity of veto by relatives over a person's positive decision to save lives by becoming a registered organ donor.
"It is vital however that the government is willing to evaluate the success of these changes after a few years and consider switching to presumed consent with opt out which has been shown to be effective in other countries.
The new guidelines will also enable a technique to be conducted to preserve organs following death until the wishes of the deceased can be established, known as non-heart beating donation.
"If we are to capitalise on the opportunities offered by non-heart beating donation then we must ensure that there is enough capacity - surgeons, beds, co-ordinators - to maximise the number of organs transplanted. It would be a tragedy if any lives were lost due to a failure by the health service to make full use of this procedure."
JOHN EVANS, CHAIRMAN OF THE BRITISH ORGAN DONOR SOCIETY
"Someone can give a witness statement that they want to be a donor, but there is no mechanism in place by which that can be checked.
"How will doctors be able to make contact with the witnesses if they suddenly need to take the organs.
"The only way of really knowing is if someone is on the national register, so more people need to sign up to it.
"This is altering the bias from asking the family to telling them what's going to happen, so it is more towards the donor's wishes.
"We are in favour of it, but we wait to see with time how effective it is."
TIMOTHY STATHAM, CHIEF EXECUTIVE OF THE NATIONAL KIDNEY FEDERATION
"The donation of a body organ from one person to another is a truly selfless and thoroughly altruistic act.
"The National Kidney Federation warmly welcomes the Human Tissue Act and in particular the recognition that such 'gifts of life' can, and will, take place between strangers."
SOLICITOR IAN COHEN, WHO REPRESENTED FAMILIES INVOLVED IN LIVERPOOL'S ALDER HEY HOSPITAL SCANDAL
"I think when you look at the Codes of Practice and the Human Tissue Act 2004 together, a lot of concerns that were raised are addressed.
"It lays out what is proper informed consent, sets out practises of how to obtain consent and deals with how to respect the wishes of families involved.
"It is putting in place safeguards so that what happened at Alder Hey will never happen again. But we must not let our guard down now.
"However, there are further aspects here that need further work, substantially more training is required for medical professionals.
"Also, under the act it makes it a criminal offence to remove and store tissue without the right consent, but what the Code of Practice doesn't do is lay out when something becomes an offence.
"This is very welcome and does deal with an awful lot of concerns - the authors have obviously listened during the consultation process."
ELIZABETH WARD, PRESIDENT OF THE BRITISH KIDNEY PATIENTS ASSOCIATION
"I think it's wrong. The whole thing is to give people a chance of a life and there is lots of tissue just lying in graveyards that could be used.
"What we need to have is an opt-out system."