Billionaire John Caudwell celebrated his 72nd birthday in style aboard his luxury superyacht Titania, moored in Monte Carlo, Monaco. Accompanied by his partner of a decade, former Olympic cyclist Modesta Vžesniauskaitė, 41, and their two young children, it was a rare moment of relaxation for the typically busy philanthropist.

According to The Sunday Times Rich List, John ranks as the 109th richest individual in Britain, with a net worth of £1.54 billion. However, the father-of-seven – who welcomed his youngest child last year – epitomises the self-made man. Born in Birmingham and brought up in Stoke-on-Trent, he started his career as an apprentice at the Michelin tyre company before founding what would become Phones 4U with his brother, Brian.

In 2006, they sold it for £1.46 billion. Today, John is hailed as one of Britain's most philanthropic individuals, spearheading Caudwell Children for disabled youngsters and the mentoring charity Caudwell Youth alongside Modesta. In his words: "There's absolutely no value in wealth if you don't do something with it that's meaningful."

John is among approximately 250 billionaires globally who have signed The Giving Pledge – a commitment to donate over half of their fortune to charitable causes, either during their lifetime or posthumously. Elon Musk, Mark Zuckerberg and Richard Branson are also signatories. John made his pledge in 2013 and is baffled as to why the list isn't longer. "I've pledged 70% during and after my lifetime. It's such a privileged position, but rich people don't generally 'get' it.

"They think I'm mad for giving my money away and for the time I dedicate to charitable causes. But of those 250 of us that do – out of maybe 6,000 – it's our duty to try and make the world a better place. Assisting those who can't help themselves is a great privilege, not a burden."

Meanwhile, he describes life with Modesta as "extremely normal, within an abnormal environment". They reside in Broughton Hall, Staffordshire, and also own properties in London and Monaco. Modesta assists in running his two charities while also caring for their two young children – Isabella, one, and William, three – and her son Leonardo, 12, from a previous relationship.

John who also owns a residence in Mayfair, London said he doesn't want anything that costs money for his birthday and instead wants "emotionally important things, that money can't buy", reports OK!.

He added: "Modesta and [son] William made me bacon and eggs this morning with a large strawberry birthday cake. I also received some nice slip-on shoes. But the most precious gift was a photo album, filled with beautiful snapshots of our lives – she involved the kids in creating some childlike designs on them.It was delightful to browse through."

John's work ethic is formidable; sometimes he logs up to 18-hour days, yet when at home, his focus is unwaveringly on family life. Despite having "an army of support" to streamline their day-to-day, John often finds himself at the helm in the kitchen, rustling up meals that his household adores.

"The bit where we're not completely normal is we do have one or two staff," he admits with a chuckle. However, his zeal for gastronomy shines through, "But I love cooking, it's a big hobby. I'm always experimenting with dishes."

His wife Modesta cherishes his culinary enthusiasm. She confesses, "I don't like cooking, but when John cooks it's like a celebration in the kitchen! Even our one-year-old loves Daddy's sauces, she always asks for more."John is quick to clarify with a chuckle, "And by Daddy's sauce she means my sauces, not the brown stuff in a bottle!"

Apart from food, John has another fervent pursuit – cycling, which incidentally led him to Modesta, a former Olympic road cyclist for Lithuania. The pair fell into step during a charity event.

"We both did a charity ride organised by Prince Albert of Monaco and spent all day chatting and enjoying each other's company," reminisces Modesta with a smile. "It seems like yesterday, and now we're still on our bikes, still loving each other, still doing charity work." But today, their bike outings include their children, Isabella and William, who join in on the fun.

John's recent business venture has been his £2 billion 1 Mayfair project, which involves transforming a former car park and hotel into 24 residences of "unprecedented scale and grandeur". His knack for transformations is evident in the case of Titania, a 73m superyacht that rents for around £525,000 a week and was featured in The Crown for the Princess Diana scenes.

This week, he's hosting his Life-Changers Circle, an exclusive group of 14 philanthropists and dedicated humanitarians who are required to donate a minimum of £100,000 a year to Caudwell Children to support projects like the Caudwell International Children's Centre in Newcastle-under-Lyme.

And while they're in Monaco, he and Modesta are also hosting their annual fundraising Butterfly Ball. John said: "If I'm going to something like Elton John's charity ball and donating on the night, all I have to do is be fairly confident the money is going to a good cause and being efficiently used, so no. But when I went on some charity visits with Elton and looked at the work being done, there was an emotional toll because we met some of the people the charity was helping."

Before Isabella and William arrived, John had three children from his first marriage – Rebekah, Libby and Rufus – and another daughter, Scarlett, and son Jacobi, from subsequent relationships.

He says of being an older dad, "I have the luxury of time now. I was building an empire the first time around. "The most important thing for me is that my kids grow up achieving happiness, and leaving the world a better place than they found it. I know that sounds cheesy but I truly believe there's nothing more important."

The couple celebrated their decade-long relationship earlier this year, sparking questions about potential wedding plans or a desire to take things easier. John remarks, "I've never really felt marriage very important. What's important is a commitment to making a relationship last – not a piece of paper. Plus, Modesta and I have so many important things to do, that's our focus."