Live organ donation from strangers will be allowed under new human tissue legislation.
The changes will help reduce organ shortages
At present, organ donation from living donors can only take place between people who are genetically or emotionally connected.
But from the autumn there will be more flexibility in who can donate to whom, which should reduce waiting lists.
The announcement was made by the Human Tissue Authority, set up to regulate use and storage of organs and tissue.
It was set up under the new Human Tissue Act which was drafted in the wake of the Alder Hey scandal, where organs were taken and stored without consent after patients had died.
The Human Tissue Act has made consent a fundamental principle underpinning the storage and use of tissue parts from live and deceased donors.
Doctors want to increase the proportion from living donor transplants as there is a greater chance of success than transplants from deceased donors.
However, regulations had forbidden donation from those who were not family or friends of the recipient.
Donations from strangers
The new legislation in the Human Tissue Act will allow "paired/pooled" and "altruistic" donation from 1 September.
Paired donation, means pairing a donor and recipient whose blood types or tissue types do not match with another donor and recipient in the same situation.
If the donor of one couple matched the recipient of the other, and vice versa, a cross-over transplantation could be performed.
A pooled donation would involve more than two couples, although this would be restricted by logistics as all of the transplants would have to take place within the same time-frame.
Altruistic donation is the donation of an organ from a stranger, although it is believed there would be fewer volunteers for this.
The new measures will mainly affect kidney transplantation, as this has a low risk to donors who can live reasonably unaffected lives afterwards.
In the last year, 1,905 kidney transplants were performed in the UK with 582 from live donors.
Baroness Hayman, chair of HTA, said: "There are transplant surgeons anxious to do this, there are families anxious to participate in this sort of process, and so we have been working with UK Transplant on setting up the processes to allow this.
"Of course, the more couples you have, the more likely you are to get a couple that match another couple."
Adrian McNeill, chief executive of HTA, said: "We expect some 40-50 additional kidney donations a year as a consequence of this new form of approval."
Timothy Statham, chief executive of the National Kidney Federation, said: "The donation of a body organ from one person to another is a truly selfless and thoroughly altruistic act.
"We welcome the recognition that such 'gifts of life' can, and will, take place between strangers."
The HTA will also regulate other practices concerning the use and storage of human tissue, organs and bodies.
Those carrying out these practices will have to apply for a licence from HTA, and will be subject to inspections.
This will affect a number of practices including post-mortem examinations, the removal of tissue from living donors, storage of anatomical specimens, and the display of a body or material from a deceased person.