LIKE many people, actress Emily Watson can distinctly remember where she was on July 7 2005 when suicide bombers coordinated attacks across London, killing 52 people and injuring more than 700.
"I was at home in London, heavily pregnant with my first child, about to go and get the tube," recalls the 48-year-old, best known for her roles in Angela's Ashes, Breaking the Waves and Gosford Park.
"We turned on the radio and heard there'd been an incident. I remember so much confusion and then the chilling moment when the bus explosion came. A 'power surge' became 'London was under attack' [at first, the explosions were thought to be down to a power fault, before the full horrifying picture emerged]."
Although Watson, who has two children with actor husband Jack Waters, wasn't "directly affected" by the attacks, she felt a "call of duty" to accept the role of a grieving mother in A Song For Jenny.
The standalone drama is based on the memoir by Julie Nicholson, a former Church of England vicar whose 24-year-old daughter Jenny was killed in the bomb blast at Edgware Road tube station.
Adapted for the screen by Co Donegal playwright Frank McGuinness, who spent the best part of four years writing the script, it captures the twist of fate that saw Jenny take the Circle line that day and traces her mother's response, from the moment she hears about the attacks to the news that her daughter is missing, and then the confirmation that Jenny is among the dead.
"Obviously, there are many stories from that day. Each unique," remarks Watson, who was born and raised in London.
"Julie is a natural storyteller, and very significantly, a priest who lost her child to what purported to be, however twisted, a religiously motivated act. Her religious faith was very shaken and she's no longer a priest. And though in honouring her daughter she drove herself to the edge, staring into a dark abyss, ultimately she chose humanity, and chose love over hatred."
The actress met Nicholson, who stepped down from the pulpit in 2006 because she felt she could no longer preach forgiveness, shortly after reading her book.
"Julie shared very intimate, raw and tender memories with me. She's incredibly generous," Watson says.
Buncrana native McGuinness, whose plays include Factory Girls and Observe the Sons of Ulster Marching Towards the Somme, was prompted to read A Song For Jenny: A Mother's Story of Love and Loss after being impressed by Julie when he saw her interviewed on the news.
“She’s an extremely quiet, extremely strong person,” he told BBC Radio Four’s Front Row this week. “I was very very impressed just by her whole approach to the horror of what had happened and about three days later I found the book in a Dublin bookshop. I started to read it – I couldn’t put it down.”
McGuinness told Front Row he had broken down twice while reading the book. “What I loved [about it] was the sheer integrity and the sheer clarity of how Julie articulates her deep personal loss and deep grief for this brilliant daughter," he said.
He contacted a producer with whom he had worked on a previous film, – A Short Stay in Switzerland, in which Julie Walters played a high-profile doctor who died by assisted suicide at the Dignitas clinic in Zurich – and urged her to read the book.
The pair met Nicholson and her family and McGuinness “talked for hours on end with her”. They assured the family that A Song For Jenny would be a collaborative process.
“Julie is an exceptionally honest woman,” the playwright said. “She was a priest and in many ways she has remained a priest in the proper sense of the word. I think that her dominant point is that she cannot forgive the bombers. It’s only up to her daughter Jenny to forgive the bombers and she, Jenny, is not there to do that. She rightly feels that she does not have the right to usurp Jenny’s moral role in this whole tragedy."
For her part, Nicholson admits it was tough to give the book over to strangers, but says "I felt privileged that someone else wanted to tell my story and Jenny's".
"Frank talked to me regularly, and I saw each draft and was able to comment and have some input," reveals Nicholson, who was also included in the process of casting somebody to play her daughter.
"I said from the outset that it wouldn't be appropriate to search for a 'lookalike' Jenny, but that an actress should be found who could capture the essence of her, ideally someone who was not already a known face."
Nicola Wren, who was eventually chosen for the role, was straight out of drama school, "which I felt Jenny would have approved of", notes Nicholson.
As to how she felt having Watson, a two-time Oscar and four-time Bafta nominee, playing her, Nicholson says "blessed".
"I believed it was important that whoever played me should be a mother, and understand viscerally the powerful bond. Emily is an extraordinary and courageous actor who takes risks. Her stillness and quietness is as powerful as her actions and spoken words. There were times when I didn't know if I was watching Emily or myself."
Watson, who starred in the Fred and Rose West drama Appropriate Adult, is no stranger to emotionally charged roles, but says this was one of her most challenging.
"Having to inhabit the deep traumatic grief and shock was pretty hard," she admits. "To contemplate what happened to Julie's daughter happening to my own, is a brink that I have to pull back from. In rehearsals, it was as if we had to stop ourselves from letting everything flow because it was too much, and we had to hold it back and wait for the camera to be there because it was so devastating.
"Enjoy is not really the word – but there was a great sense of serious commitment among the cast and crew. Unlike anything I've experienced."
Nicholson has watched an early screening of the drama, and notes: "I felt like I had Jenny back again for a while, but then of course, I had to lose her all over again.
"The scenes with Jenny and her sister and brother were funny and joyous. It was very poignant watching my father, uncle and aunt, who are no longer here, and I felt the film captured all the relationships so well," she continues.
"I wept, of course, I think from beginning to end. I feel that something very beautiful has been created, a painfully bittersweet gift, but nonetheless, a gift."
:: A Song For Jenny airs on BBC One on Sunday.