Prosecutors said Sharaz Ali, 40, was "motivated by jealousy and fuelled by drink and drugs" when he set fire to Bryonie Gawith's home early on 21 August last year.
Jurors heard that Ali went to the home in Westbury Road, Bradford, aiming to "take revenge" on his ex, Antonia Gawith, who was staying there after ending their "abusive" seven-year relationship earlier that month.
Antonia Gawith managed to escape, but Bryonie Gawith, 29, and her children Denisty Birtle, nine, Oscar Birtle, five, and 22-month-old Aubree Birtle died in the blaze.
Ali told a jury he had no intention of harming others when the house went up in flames, saying: "I didn't want to hurt anyone but myself."
But after a trial at Doncaster Crown Court, he was found guilty of four counts of murder and attempting to murder Antonia Gawith.
Calum Sunderland, 26, who went with Ali to the house and kicked the door in for him, was found guilty of the manslaughter of Bryonie Gawith and her three children, but cleared of the more serious charges of murder.
He was also cleared of attempted murder, and an alternative count of attempting to cause grievous bodily harm, in relation to Antonia Gawith.
Mohammed Shabir, 45, who had also been due to go on trial, died of a heart attack in October after collapsing in prison.
Reading a statement on behalf of her family outside court, Antonia Gawith said her sister, nieces and nephew's futures have been "stolen".
"Even with justice, nothing will ever make this right," she said.
"Nothing will ever fill the silence where their laughter should be. Nothing will ever bring back our family.
"We will forever carry this brokenness, and yet we will hold on to them tightly in only ways we can now, through our memories, our photos and our precious videos. Those are all we have left now."
After the verdicts, the judge, Mr Justice Hilliard, thanked jurors and said the case had been "distressing beyond measure - three children and their mother murdered".
"I don't think anyone who heard Antonia's desperate cries for help will ever forget them," he said.
"These are truly dreadful crimes."
The judge also praised the "extraordinary bravery" of those who tried to save the children trapped in the house.
Ali and Sunderland, a convicted arsonist, were driven to the house by Shabir, stopping on the way to fill a seven-litre canister with petrol, the court heard.
Doorbell footage captured Ali telling Sunderland, who was carrying the petrol and a lighter, to "kick the door in", which he did before running back to the car.
Antonia Gawith said she saw an "angry" Ali run into the house and begin pouring petrol on her while shouting before setting himself and the house on fire.
'I couldn't save them'
In a video interview played to jurors, she sobbed as she told police how she "couldn't save" her sister, nieces and nephew, as she tried frantically to get back in the house through the back door.
"I was just screaming, trying to get back in the house and I couldn't get in. I couldn't save them," she said.
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West Yorkshire Police's Detective Chief Inspector Stacey Atkinson said: "Bryonie and her three children would still be alive today if it wasn't for the horrific and truly callous actions of Ali and Sunderland that day.
"They left a mum and her three children completely helpless whilst her sister and their auntie watched on in horror.
"Our thoughts and sympathies are with the family, who despite their immense strength of character now face the rest of their lives without them."
Senior Crown Prosecution Service prosecutor Amanda McInnes said Ali was a "selfish killer who had no regard for anyone but himself".
"He was motivated by jealousy and his actions have now needlessly robbed a family of their loved ones," she said.
"Both men played their role and caused the deaths of a young family who should still be with us today."
The writer, whose real name was Madeleine Sophie Wickham, revealed last year she had been diagnosed with an aggressive form of brain cancer in 2022.
A statement posted to her Instagram account read: "We are heartbroken to announce the passing this morning of our beloved Sophie (aka Maddy, aka Mummy). She died peacefully, with her final days filled with her true loves: family and music and warmth and Christmas and joy.
"We can't imagine what life will be like without her radiance and love of life.
"Despite her illness, which she bore with unimaginable courage, Sophie counted herself truly blessed - to have such wonderful family and friends, and to have had the extraordinary success of her writing career. She took nothing for granted and was forever grateful for the love she received.
"She will be missed so much our hearts are breaking."
Kinsella's novels have sold more than 45 million copies in more than 60 countries, and have been translated into more than 40 languages.
In April 2024, she revealed she had been diagnosed with an aggressive form of brain cancer in 2022.
In a post on social media, Kinsella said she had been receiving chemotherapy and radiotherapy at London's University College Hospital, and had undergone "successful" surgery.
She said she "wanted for a long time to share with you a health update and I've been waiting for the strength to do so".
"At the end of 2022 I was diagnosed with glioblastoma, a form of aggressive brain cancer," she said.
"I did not share this before because I wanted to make sure that my children were able to hear and process the news in privacy and adapt to our 'new normal'.
"At the moment all is stable and I am feeling generally very well, though I get very tired and my memory is even worse than it was before!
"I am so grateful to my family and close friends who have been an incredible support to me, and to the wonderful doctors and nurses who have treated me."
Kinsella's most recent book is What Does it Feel Like?, published in October 2024 and which "is fiction, but it is my most autobiographical work to date", the author wrote on her website.
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Other books by the London-born author include The Burnout, released in October 2023, Can You Keep A Secret? and The Undomestic Goddess.
The first two novels in her hit eight-book Shopaholic series, The Secret Dreamworld Of A Shopaholic and Shopaholic Abroad, were adapted into the 2009 film Confessions Of A Shopaholic, starring Isla Fisher.
She is survived by her children, four sons and a daughter, and her husband Henry Wickham.
Bill Scott-Kerr, publisher at Transworld, the publishing home of Kinsella for the past 30 years, said: "She has been such an unshakeable pillar of our publishing at Transworld for so many years that the thought of a year without a Sophie Kinsella to publish is inconceivable."
He added: "Maddy leaves behind a glorious and indelible legacy: a unique voice, an unquenchable spirit, a goodness of intent and a body of work that will continue to inspire us to reach higher and be better, just like so many of her characters.
"On a personal level Maddy was the embodiment of joy, an extraordinarily clever, funny, sassy, impish, kind and generous collaborator who brought light into our lives. She was as part of this company as anyone, and we will all truly miss her."
Seattle's PrideFest 2026, which organisers say regularly sees more than 200,000 participants, takes place on 27 and 28 June - immediately following the match.
Local organisers have said the 26 June game at the Seattle Stadium will include a "once-in-a-lifetime moment to showcase and celebrate LGBTQIA+ communities in Washington".
In Iran, where gay couples can face the death penalty, the president of Iran's Football Federation, Mehdi Taj, condemned the decision to use Seattle as a venue and the timing of the match.
Mr Taj told Iranian state TV: "Both Egypt and we have objected, because this is an unreasonable and illogical move that essentially signals support for a particular group, and we must definitely address this point."
He said Iran would bring up the issue at a FIFA Council meeting in Qatar next week.
The football federation in Egypt, where Human Rights Watch says people from LGBTQ+ communities face persecution, said in a statement that it had written to FIFA "categorically rejecting any activities related to supporting homosexuality during the match between the Egyptian national team and Iran."
The letter also stated: "Information had circulated indicating the local organising committee's decision and plans to hold some activities related to supporting homosexuality during that match" and the federation "completely rejects such activities, which directly contradict the cultural, religious and social values in the region, especially in Arab and Islamic societies".
In Seattle, the local organising committee said it was "moving forward as planned with our community programming outside the stadium during Pride weekend and throughout the tournament," having already promoted an art contest ahead of the match.
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It added: "We get to show the world that in Seattle, everyone is welcome."
Seattle PrideFest has been organised in the city since 2007 by a nonprofit group which designated the 26 June match for celebration before FIFA carried out the World Cup draw on Friday.
On Saturday, FIFA announced the Egypt-Iran game had been allocated to Seattle instead of Vancouver, where the teams' group rivals Belgium and New Zealand will play at the same time.
FIFA has been asked for a comment.
Parents across Australia are reported to have found their children distraught after discovering they had been shut out of online platforms.
Some children are said to be fooling age estimation technology by drawing on fake facial hair or using parents and older siblings to dodge the implementation of the ban.
From Wednesday, a host of social media sites face fines of up to $49.5m (£25m) if they fail to take reasonable steps to remove the accounts of the banned teenagers.
While Australian Prime Minister Anthony Albanese described the move as "the day when Australian families are taking back power from these big tech companies", many young people used their last few hours to criticise the government.
The prime minister, who has lost over 6,000 followers across TikTok and Instagram since Tuesday, has borne the brunt of anger about the ban's introduction, which he warned "won't be perfect".
One comment on his TikTok account read "just wait until we're able to vote", another said, "still here mate".
Parents whose children have large social media followings and use online platforms as part of their businesses raised alarm over the financial impact of the ban.
Simone Clements said the social media ban would come at a financial cost to her 15-year-old twins Carlee and Hayden Clements. Carlee is an actor, model, dancer, singer and influencer, while her brother is an actor and model.
Both have used social media to grow their following online and income stream.
Two teenagers have even launched a legal bid to try and challenge the ban.
However, despite the criticism, the ban has been widely welcomed by many.
Wayne Holdsworth, whose son took his own life after being targeted in an online sextortion scam, described the law as a start.
Holdsworth, who became an age restriction advocate following his son's death, said: "Our kids that we've lost haven't died in vain because today they'll be looking down very proud of the work that we've all done."
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Flossie Brodribb, a 12-year-old advocate for a social media ban for young children, described the plan as bold and brave.
She added: "It will help kids like me to grow up healthier, safer, kinder and more connected to the real world."
The government has said it will report by Christmas if the under-16 social media ban is working.
Communications minister Anika Wells warned children who had managed to evade the start of the ban that they would eventually be caught.
"Just because they might have avoided it [detection] today doesn't mean they will be able to avoid it in a week's time or a month's time because social media platforms have to go back and routinely check under-16 accounts," she said.
Ms Wells added that more than 200,000 TikTok accounts in Australia had already been deactivated.
New Ofcom data raises UK concerns
Countries around the world are watching Australia's new ban closely due to concerns social media use among young people could be causing harm.
New Ofcom figures show children in the UK between eight and 14 are spending an average of nearly three hours online each day - often late at night.
According to the data, almost a quarter of time spent by that age group on their four main social media services happened between 9pm and 5am.
While Ofcom found about 91% of those aged eight to 17 in the UK were happy with their online activity, 70% of 11 to 17-year-olds saw or heard harmful content online over a four-week period.
The data also raises concerns over children spending money online on social media sites, video-sharing platforms or while gaming - with more than half of children aged eight to 17 having done so in the past month.
Around a third of children regretted their in-game purchases and 43% regretted those made on social media.
Alarmingly, some 42% were unclear on what they even were buying in-game.
Former UK education secretary Lord Nash highlighted earlier this month how social media use seems to often start at an even younger age.
He warned that new analysis by the Centre for Social Justice suggested more than 800,000 UK children aged between three and five were already engaging with social media.
Anyone feeling emotionally distressed or suicidal can call Samaritans for help on 116 123 or email jo@samaritans.org in the UK. In the US, call the Samaritans branch in your area or 1 (800) 273-TALK.
The Quality Care Commission (CQC) surveyed 16,750 women who gave birth in February about the NHS maternity service care they received while pregnant, in hospital during and after labour, and once at home in the weeks after their baby's birth.
The results suggested improvements in some areas of NHS maternity care, but key issues remain.
Fifteen per cent of those who took part in the survey felt they were not given appropriate advice and support when they contacted a midwife or the hospital at the start of their labour.
And nearly one in five (18%) reported that they felt that they were not taken seriously if they raised a concern during their labour and birth. Both figures were unchanged from the previous year.
The survey also found that one in 10 women reported being left alone at a time when it worried them, either during the later stages of labour or during birth, the was figure unchanged from 2021.
The CQC found that slightly more women had a good experience in several areas compared to previous surveys.
Some 89% said they were always spoken to in a way they could understand by staff providing antenatal care during pregnancy (up from 88% last year).
And 81% were always given enough time to ask questions or discuss their pregnancy (up from 80% in 2024 and 73% in 2021), while 77% felt they were always involved in decisions about their care during labour and birth (up from 75% in 2024).
Far more women said their husband, partner or someone close was able to stay with them as much as they wanted after the birth (72% compared to 63% last year).
There were also slight improvements on women being asked about their mental health and knowing who to contact if they were having problems.
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How do different NHS trusts compare for maternity care?
The report identifies the proportion of NHS trusts where people's experiences were better or worse than would be expected compared to other trusts.
Overall, around one in 10 trusts were classified as performing worse than the standard on postnatal care in the ward - only 6% performed better.
Six trusts achieved "worse than expected" results overall, while two achieved "much worse than expected results". Five were characterised as better than expected, down from eight last year.
The share of c-section births has been rising steadily. In 2023/24, two in five births were c-sections, according to NHS maternity data from 2023/24 - an increase from one in four a decade earlier. More than half of caesareans (56%) were classed as emergency or unplanned c-sections.
Women who saw same midwife had more positive experiences
Overall, 57% of women were always able to get a member of staff to help them when they needed it while in hospital after birth, but one in 10 said they could not get help when they needed it at all - figures largely unchanged from 2021.
Seven per cent of women said they were sent home once when they were worried about themselves or their baby, with 3% saying this happened more than once.
Women who saw the same midwife throughout their pregnancy tended to be more positive about their experiences, but those from the most deprived neighbourhoods were less likely to feel treated with dignity and respect.
The data comes after the head of a maternity review said NHS maternity units are delivering "unacceptable care" - with some women left to "bleed out" in bathrooms and babies suffering avoidable deaths.