Prof. Sir Robert Edwards, the pioneer of IVF, has died in his sleep after a long illness at the age of 87.

Robert Edwards was knighted in 2011, five decades after he began experimenting with IVF.

IVF is used worldwide and has resulted in more than five million babies.

His work led to the birth of world’s first test-tube baby Louise Brown at Oldham General Hospital in 1978.

Robert Edwards was knighted in 2011, five decades after he began experimenting with IVF

Paying tribute to Prof. Robert Edwards, Louise Brown said he had brought “happiness and joy” to millions of people.

She said: “I have always regarded Robert Edwards as like a grandfather to me.

“His work, along with Patrick Steptoe, has brought happiness and joy to millions of people all over the world by enabling them to have children.

“I am glad that he lived long enough to be recognized with a Nobel prize for his work, and his legacy will live on with all the IVF work being carried out throughout the world.”

The University of Cambridge, where Prof. Robert Edwards was a fellow, said his work “had an immense impact”.

Born in Yorkshire in 1925 into a working-class family, Robert Edwards served in the British army during World War II before returning home to study first agricultural sciences and then animal genetics.

Building on earlier research, which showed that egg cells from rabbits could be fertilized in test tubes when sperm was added, Robert Edwards developed the same technique for humans.

In a laboratory at Cambridge in 1968, Robert Edwards first saw life created outside the womb in the form of a human blastocyst, an embryo that has developed for five to six days after fertilization.

“I’ll never forget the day I looked down the microscope and saw something funny in the cultures,” he once recalled.

“I looked down the microscope and what I saw was a human blastocyst gazing up at me. I thought, <<We’ve done it>>.”

“Bob Edwards is one of our greatest scientists,” said Mike Macnamee, chief executive of Bourn Hall, the IVF clinic founded by Prof. Robert Edwards with his fellow IVF pioneer Patrick Steptoe, a gynaecological surgeon.

Robert Edwards was too frail to pick up his Nobel prize in Stockholm in 2010, leaving that job to his wife Ruth, with whom he had five daughters.

He remained a fellow of Churchill College, Cambridge, until his death.

Robert Edwards’ work was motivated by his belief, as he once described it, that “the most important thing in life is having a child.”