London

Biographical drama "Joy", which received its world premiere at the London Film Festival on Tuesday, depicts the decade-long efforts of three British medics and scientists to develop the technique of in vitro fertilisation (IVF).

The movie centres on the lesser-known story of nurse and embryologist Jean Purdy, played by Thomasin McKenzie, who joins physiologist Robert Edwards (James Norton) and gynaecologist Patrick Steptoe (Bill Nighy) on their quest to treat infertility.

The ups and downs of their trials and lab work are shown in detail and the film, which spans from the late 1960's to the late 70's, also delves into the toll the negative public perception of the venture took on their private lives.

"It's a huge responsibility to tell Jean's story and also just to tell the story of IVF because it's had such a massive impact on the world," McKenzie said of portraying Purdy, whose contributions went unrecognised for a long time.

"Jean Purdy was, as is traditional, airbrushed out of the whole affair," added Nighy. "So, the fact that this places her in the middle of the story, is a big part of its appeal for me."

"Joy" marks the feature film directorial debut for Ben Taylor, whose background is in television. Its subject matter hit close to home for Taylor and screenwriters, real-life couple Rachel Mason and Jack Thorne.

"It's a really personal story, because we've got IVF babies," said Taylor. "I just feel this enormous sense of gratitude towards these three people. I think for anyone that has ever been touched by infertility or IVF or knows somebody that has, it's a lot to watch because it's a very emotional subject."

Louise Joy Brown, the first human to be conceived by the trio's procedure, who was born in 1978, also attended Tuesday's premiere.

"Without them, those three, I wouldn't be here, nor would 12 million of us. So, it's not just a few of us, there are quite a few now," she said.

"Joy" starts streaming on Netflix on November 22.