Robert Edwards, the British scientist whose pioneering research with his late colleague Patrick Steptoe led to the birth of the world’s first "test tube baby" in 1978, has won this year’s Nobel Prize for medicine.

The Nobel Assembly at Sweden's Karolinska Institute, which awarded the prize worth ten million Swedish Kronor, described his work as "a milestone of modern medicine".

“His work has made possible the treatment of infertility, a medical condition that affects a large proportion of humanity including more than 10% of couples worldwide," it said in a statement.

The 85-year-old scientist was reported to be too ill to comment, but his wife Ruth and family said they were "thrilled and delighted".

"The success of this research has touched the lives of millions of people worldwide. His dedication and single-minded determination, despite opposition from many quarters, has led to the successful application of his pioneering research," they said.

‘A well- deserved honour’

Professor Basil Tarlatzis, past-president of the International Federation of Fertility Societies, called it "a well- deserved honour" and said IVF had "opened new avenues of hope for millions of couples throughout the world".

But, perhaps, no one was more delighted than Louise Brown who owed her birth to the fertility treatment (in-vitro fertilisation or IVF) devised by Professor Edwards and Steptoe.

"It's fantastic news. Me and mum are so glad that one of the pioneers of IVF has been given the recognition he deserves. We hold Bob in great affection and are delighted to send our personal congratulations to him and his family at this time," said Ms. Brown, now 32.

Her birth on July 25, 1978, prompted headlines around the world. Since then some four million babies have been born using IVF.

For Prof Edwards and his colleagues it was a "eureka" moment when they discovered that they had succeeded in creating a fertilised human embryo in 1968 but it took another ten years before the procedure was sufficiently refined to enable the birth of a baby.

"I'll never forget the day I looked down the microscope and saw something funny in the cultures. I looked down the microscope and what I saw was a human blastocyst gazing up at me. I thought: 'We've done it,'" Prof Edwards recalled in a speech two years ago.

Born in Manchester in 1925, Prof Edwards started his research on human fertilisation at the National Institute for Medical Research in London in 1958, and later moved to Cambridge where, with Steptoe, he founded the Bourn Hall Clinic, the world’s first IVF centre.

Steptoe died in 1988. Despite his significant contribution, he cannot be jointly awarded with Prof Edwards because rules do not permit for the prize to be awarded posthumously.