The technique could one day be used to patch up diseased and damaged organs, removing the agonising â€“ and sometimes unsuccessful â€“ wait for a transplant.
The manmade tissue could also be used to test new medicines, preventing disasters such as the â€˜Elephant Manâ€™ drug trial, in which six men were left fighting for their lives.
New kidneys, lungs and pancreases could be grown using the same technique.
The research is still at a very early stage but British experts have described it as a â€˜huge step forwardâ€™ and as holding out â€˜real promiseâ€™ for an alternative to organ transplants.
More than 7,000 Britons are on the transplant list, including 154 children.
The vast majority are waiting for new kidneys but almost 500 are in need of a liver and around 250 are waiting for healthy lungs to become available.
The Japanese researchers used the three types of cell that generate the liver in a human embryo to grow a tiny piece of tissue in a dish.
It was then grafted on to a mouseâ€™s brain, where it hooked up to the blood supply and grew for at least two months.