The morning of July 7, 2005, was a normal day in her London life as she rode the packed tube to work at the UK Design Council.

The critical difference was that she was uncharacteristically late that day and was on a tube she wouldn't normally catch.

Then "everything changed in the click of a finger".

Twenty-six people died in that carriage - Hicks should have been the 27th. Death actually lured her in, and she was clinically dead three times that morning, her heart stopping for a total of 29 minutes.

During the third attempt to revive her, the head of the resuscitating team at St Thomas' hospital in London gave her a final deadline of three and a half minutes.

"In three minutes the monitor showed my heart had come back, so I'm here by 30 seconds," she said.

"Amazing, isn't it? Totally amazing. I just can't get over it.

"They're still trying to piece together why I'm here."

Hicks knows why. And although she has wrestled with the concept of fate ever since she woke up two days after the blasts, she believes there's one simple reason she's still alive.

"Gill Hicks must make a difference," she says.

Since walking out of hospital on prosthetic limbs three months after the bombings, Hicks has dedicated herself to doing just that.

Rather than continuing her successful career in design, she founded the charity MAD For Peace and has devoted her life to the cause.

MAD (Making A Difference) For Peace promotes peace in its books, films and events such as the 435km walk from Leeds to London led by Hicks in 2008.

The walk went through 22 towns and cities where walkers encouraged people from varied faiths and communities to talk and engage with each other.

Her theory was that if she could walk 435km, anyone can walk across the street to talk to their neighbour.

Hicks continues the Walktalk project all over the UK and also goes to schools in Britain and her native South Australia pushing to have peace and understanding put on the curriculum.

She says the bombings have made her appreciate life and filled her with unconditional love. Every day she thanks the rescue teams and medical staff who helped save her life. And she's happy to be alive.

But it doesn't mean she's not angry.

"I have days when I'm absolutely angry. There's nothing good about having no legs," she says.

"I try to use that anger to motivate me in positive ways to make a difference, rather than destructiveness.

"But peace is tough. Peace for me isn't about some warm fuzzy tree-hugging rainbow-colour-wearing experience, it's tough. Peace is challenging and gritty and tough, and it takes hard work and absolute determination to make a choice.

"Life's too important to be pent up over this rubbish that I've encountered.

"I'm so filled with absolute love that my whole life has changed as a result of it."

Many people can't understand her attitude, and she's often misconstrued as being soft on terror.

But hatred for those who maimed her and killed 52 others, including Melbourne man Sam Ly, doesn't enter her world.

"Hatred led to this, I can't let hatred fuel it even more. That would be an absolute waste of my life," she says.

When fiance Joe Kerr told her the train had been destroyed by a bomb rather than an accident as she had thought, she wanted to see the face of the "monster" responsible.

Germaine Lindsay, 19, was standing two people away from Hicks on the packed Piccadilly line train, with a bomb in his backpack.

But Hicks can only feel pity for a young man who felt compelled to give up a child and a pregnant wife to kill himself and others.

When Kerr showed her a newspaper, the image looking back at her wasn't the monster she was expecting.

"I wanted to see his face," she says.

"It was very odd, he just looked like this normal person. The overwhelming thing I felt was pity that that's what he decided to do. I thought, `You presumed I was your enemy. If only you'd asked me, if only we had a conversation about this disposable means by which you wanted to make a difference.'

"What I'm trying to show is that you can make a difference, but you can make a difference in a very different way."

Lindsay and the other three home-grown Islamic extremists all came from the Leeds suburb of Beeston, an area where Hicks spends a lot of time campaigning for peace and being welcomed with open arms. And getting people to talk.

"I've tried to get back down to absolute grass roots and community level," she says.

"The thing that I can change is my home. If that theory can be rolled out, then we'll have more peaceful neighbourhoods, more peaceful communities, more peaceful cities."

Hicks is driven by what she saw on the morning of July 7 - "the absolute best of humanity".

"One person tried to take my life, but so many risked theirs to save me - entering that scene, not knowing if there'd be a secondary device, not knowing if the tunnel would collapse, they did everything they could to save this One Unknown.

"No one gave up trying to save my life."

She will mark the bombings' fifth anniversary as she has every year - with an open house at her London home with the rescuers and medical staff who saved her life and have since become like family.

She still remembers the moments after the bomb and having enough clarity to elevate what was remaining of her legs, to slow her breathing and concentrate.

"Focus, focus, focus. I stared at my watch. Those of us who were still alive were talking to each other in the carriage," she says.

"The only time I ever really panicked was when I thought, `Do they know we're down here?'"

The survivors waited an hour until the lead paramedic, who is now one of Hicks' closest friends, entered the carriage.

She drifted in and out of consciousness while being taken out of the 30-metre-deep tunnel but remained conscious enough in hospital to blink at the right letters to spell out her name.

Before she identified herself as Gill Hicks, she was referred to as "One Unknown" who was "estimated female".

She puts her survival down to "a mixture of great human achievement and a bit of divine intervention - and being Australian".

"There was a lovely comment from my surgeon ... he found out I was Australian and said, `Ah, that makes sense'. That's what he saw, that sort of spirit I'm not going to get beaten by this."

She still has a strong tie to Australia and comes home several times a year to give motivational speeches and work for peace and the disabled and has also spoken to survivors of Victoria's 2009 bushfires.

But for the last year she has travelled alone.

For a woman filled with unconditional love and forgiveness, it's a sad irony that her marriage, which was such a crucial part of her survival and recovery, has failed.

Her courage and spirit carried her to her wedding at the 13th century St Etheldreda's church in London, where she walked down the aisle to marry Kerr five months after having her legs blown off.

She and Kerr separated a year ago and are currently going through an amicable divorce.

"I left Joe. What was very hard for me to say to him was that the vow I had given myself, in how I must live my life, is greater than the vow I gave him at our wedding. And that's a really tough thing for me to understand and to say," she says.

"The vow was the contract. That was an adamant vow. Really, really strong things happened in that carriage to me, and I will never ever dishonour that. I will do everything I can to fulfil that promise to myself.

"The hardest thing was to leave a marriage. Once again, I'm stepping into the unknown."

Her next venture into the unknown is an audacious plan which is scaring her physios.

"I want to climb a mountain," she says, adding she's eyeing off the 4500-metre Mont Blanc in France.

"It's symbolic. We can all get over our mountains."