The first baby in Britain to be screened for a deadly breast cancer gene while still an embryo has been born safely in London.

Her parents, who wish to remain anonymous, opted for screening because three generations of women in the father's family had suffered the disease.

Had the baby been born with the BRCA1 gene she would have had an 80 per cent chance of developing breast cancer as a direct result and a 60 per cent chance of ovarian cancer.

"This little girl will not face the spectre of developing this genetic form of breast cancer or ovarian cancer in her adult life," said Paul Serhal, of University College London, where the child was delivered.

"The parents will have been spared the risk of inflicting this disease on their daughter. The lasting legacy is the eradication of the transmission of this form of cancer that has blighted these families for generations."

Mr Serhal, medical director of the hospital's assisted conception unit, led the team that screened 11 embryos for the couple last year. Five of the embryos were found to be free of the BRCA1 gene and two were implanted in the mother's womb, one of them developing into a baby.

Announcing the baby's safe arrival, he said he was "absolutely delighted" with the progress of mother and baby and added: "They are very well and we are very pleased. That is all I am allowed to say."

The mother, then 27, said in June last year that she and her husband felt they had to make the effort to protect their children from the gene. "For the past three generations, every single woman in my husband's family has had breast cancer, as early as 27 and 29," she said.

"We felt that, if there was a possibility of eliminating this for our children, then that was a route we had to go down. It has been successful for us which means we are eliminating the gene from our line.

"We had been through his sister being ill, so it was something we had seen first hand. I thought this was something I had to try because, if we had a daughter with the gene, and she was ill, I couldn't look her in the face and say I didn't try."

The technique used to ensure that the girl would be born free of the cancer gene is called pre-implantation genetic diagnosis (PGD) and has been used previously in Britain to prevent babies being born with more than 60 inherited disorders, including cystic fibrosis and Huntington's disease.

Permission for the procedure being used to stop the BRCA1 gene being passed on was granted by the Human Fertilisation and Embryology Authority after a public consultation.

Dr Sarah Cant, policy manager at Breakthrough Breast Cancer, said: "The decision to screen embryos to see whether they have a faulty breast cancer gene is a complex and very personal issue.

"Women with a family history of breast cancer tell us that what might be right for one person may not be right for another.

"It's important for anyone affected to have appropriate information and support so they can make the right choice for them."

Faulty genes are responsible for between 5 per cent and 10 per cent of the 44,000 cases of breast cancer that occur in the UK each year.

BRCA1 and its sister gene BRCA2 are the two most commonly involved. Women with a defective BRCA1 or BRCA2 gene are up to seven times more likely to develop breast cancer than those without the mutations.