Claire Throssell missed seeing her sons by five minutes. She was on her way back from work when they set off for a visit to see their father.

When police knocked on her door later that night, her first thought was: "What has he done?"

Her estranged husband, Darren Sykes, had started a fire in his home while Jack, 12, and Paul, nine, were inside the attic looking at a train set, then locked them in.

The unsupervised access visit had been sanctioned by the family court despite evidence that Sykes had abused both his sons and Claire, and was capable of harming them.

Paul died on that same night, 22 October 2014, and Jack passed away a few days later, believing he had saved his younger brother's life.

Claire made Jack a promise while he lay in her arms in hospital - and this week she feels like, more than a decade on, she kept that promise.

Claire, from Penistone near Barnsley, has spent 12 years campaigning to change the law around presumption of parental involvement, which assumes children benefit from contact with both parents after separation, and on Tuesday she saw the Courts and Tribunals Bill go through its final stages in the Commons.

That means it will become the law she has spent so long fighting for.

I remember sitting in her front room more than a decade ago, nearly a year to the day after the boys were killed.

Some people's nightmares stay with you for a long time.

But Claire has gone through what happened to her, Jack and Paul, thousands of times, in incredibly intricate detail, with hundreds of different journalists.

All because she wanted to keep doing her best to keep her promise.

"There are many days when they are dark. I can sit and think 'how do I get through the next minute?' Never mind the next hour or the next day.

"But then I remind myself that that are dozens of children that don't have that day tomorrow and I've kind of made it my mission to try and educate other people.

"For anyone at risk of harm there is only today, there is no tomorrow and if we can do something better, do it today."

Twelve years on, 2026 marks the year that Jack has been dead for as long as he was alive.

"The right thing to do is love. The right thing to do is take the boys' love and move it forward and share it with the world. Make difference in their names and make a legacy that will last," Claire explains.

"This year, Jack will have been sleeping as long as he was alive. It never feels like a victory, how can it because the boys are not here anymore.

"But it does fell like this is a step to the future, to give generations of children to come, a safe, happy life, free from fear."

Looking back, Claire now realises that Sykes, who also died in the fire, had been manipulative and controlling throughout their relationship.

After they met through work, there were too many flowers, too many phone calls, too much interest in where she was.

That turned into insults, shouting and physical abuse. His behaviour got worse after they married and had Jack and Paul.

By 2014, she had left and moved in with her mother. Custody of the boys was shared.

The boys told social workers that they were scared of their father. Paul told them he was "pure nasty".

Claire also had tried to tell authorities that she was scared of what Sykes was capable of.

She submitted statements to the courts that he'd told her "he had nothing to live for" and that he could "understand fathers killing their children".

His access to his children was limited - but, crucially, unsupervised visits were still allowed.

One of those visits was after school on the day of the fire.

Jack, a Toy Story fan, responded with his usual "to infinity and beyond," mimicking the catchphrase of the Buzz Lightyear character from the movie.

She noticed that Jack, who normally looked back at her while he was going into school, turned and looked a second time and issued the same line as his brother.

Their father had texted that morning saying the boys could play with the train set in the attic.

He said he had "two new trains. all he needed was two drivers".

Later he set up the track and then lit 14 separate fires, making sure they could not escape. Jack tried to drag Paul towards the attic door, and was found on the landing.

He was able to tell a firefighter who rescued him: "My dad did this and he did it on purpose."

Jack's determination to make sure people knew the truth while he was still able to tell them has driven Claire on.

"What I've done in the many dark times in the last 12 years is I've taken Jack's courage. The fact he made a conscious decision to think about other people even though he was dying.

"He thought he'd saved his brother's life."

Paul was alive until Claire arrived at Sheffield Children's Hospital.

She says he smiled at her then the light went out of his eyes.

"He just fell asleep in my arms."

Jack was taken to hospital in Manchester, but died as Claire held him five days later.

It was the same day he had been due to have an interview with family court representatives about his father.

Claire believes that changing the family court presumption, that children should have contact with both parents, will save lives.

"This is not aimed at good parents. This will not affect good parents. This will not affect their access to their children. It will not affect their rights.

"What it will do is look at an abuser that's known to the courts and will say 'you don't have automatic access to your children'.

"It will not presume you're safe."

Not everyone agrees with Claire, The Conservatives tabled an amendment which attempted to keep presumption of contact.

In the debate, South West Devon MP Rebecca Smith MP questioned why the removal of the presumption was needed.

"Courts already have the power to restrict unsafe contact. The presumption of parental contact is already qualified by risk of harm to the child, so why do we need this clause at all?

"In some cases this would increase the state's power to erase one parent from a child's life and we know that is often their father."

Claire says that removing the presumption puts children at the front of decision-making - which would keep them safer.

She also says the Conservative government was told in 2020 that the presumption of contact needed an urgent review.

Ultimately the removal of presumption of contact was voted through.

Claire was in the public gallery of the Commons this week, holding a photograph of her sons and said the feeling was "absolutely incredible".

"I felt Jack and Paul. I couldn't quite believe what I'd heard.

"I've talked about hope and how if you don't have hope you have nothing. If you can't hope that things are going to get better in your life then you're in a dark, dark place indeed."

The toll that campaigning takes on Claire is clear.

As journalists, we often talk to people who have lost family members in tragic circumstances.

It always amazes me how they have the strength to go on to campaign, raise money, change laws and save lives.

The drive it must take, the effort they put in and the toll it takes on them perhaps isn't talked about enough.

"I've come out of debates and wanted to throw myself under a bus," she says simply.

"But the reality is, I'm sat in Parliament but tonight I'll be walking into an empty home.

"No shoes at the door to trip over, no trumpet playing, no arguments, no noise, nobody to hold my hand.

"So, yeah we've changed the law, but my life won't change.

"For this to be their legacy will be incredible."

"All you want from your kids is to be proud of you and say 'well done Mum'."

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