LONDON (Reuters) - Scientists said on Wednesday they had created Britain's first human embryonic stem cell line, clearing the way for more research into diseases including diabetes and Parkinson's.

The team, at King's College London, said the new line -- a string of many identical cells -- would be deposited in the Medical Research Council's $4.2 million stem cell bank, which was launched last year.

Stem cells hold the promise of treating a range of medical conditions but their use is controversial because although they are found in adult tissue, the most flexible stem cells come from early embryos.

In this case, the researchers said they obtained three stem cell lines from 58 embryos. Two cell lines perished but the remaining one had now been growing for many months.

"We are very excited about this development," said Dr Stephen Minger, one of the leaders of the team whose work was published in Reproductive BioMedicine Online.

"Human embryonic stem cells are found in the earliest stages of development and are capable of giving rise to all the different types of cell in the body. This means their possible therapeutic uses are almost endless."

Minger told Reuters the researchers were particularly interested in research aimed at generating new cells for transplantation in diabetes and Parkinson's disease (news - web sites), and possibly also for patients with heart disorders.

Traditionally, stem cell lines have been created with great difficulty using cells from embryos surplus to IVF, which are often of poor quality.

But in this case, high-quality embryos were donated by women undergoing pre-implantation genetic diagnosis because they were known to be at risk of passing on serious genetic disorders if they had children.

Only embryos unaffected by these disorders were replaced into the women. Cells from the remaining embryos, which were unsuitable for replacement and would normally have perished, were used to generate the stem cell lines.

The Kings College team was one of the first two laboratories in Britain to be granted a license by the Human Fertilization and Embryology Authority to generate human embryonic stem cells.