Now happily settled in Los Angeles, Adele dropped by the 21st birthday party of her friend Harry Styles at a fashionable West Hollywood bar and gave him a signed copy of her iconic album, 21, with a note saying: “I did some pretty cool stuff when I was 21. Good luck!” Harry, who thought Adele was amazing, was thrilled.

It was February 2015 and her second album had already become the best-selling release of the 21st century. It was a triumph, rising from the ashes of yet another toxic relationship that inspired such classics as Rolling in the Deep, Rumour Has It and the heartbreaking Someone Like You – the song with which she held the audience at the 2011 Brit Awards spellbound.

Yet despite her success, in her landmark interview for next month’s Vogue magazine, she admits in typically outspoken Adele fashion: “I was drunk as a fart on 21. I really don’t remember much, I just remember being really sad.”

This wasn’t the first time she had channelled fury and regret into memorable music. She was literally lurching from one bad relationship to the next.

One of the most famous songs from her debut album, 19, came about when she was devastated to learn her first serious boyfriend had been cheating on her.

She marched into the West End bar where he was drinking, told him what she thought of him and “punched him in the face”. She was swiftly escorted from the premises.

Everything might have been different if the straying boyfriend had run after her and they had made up there and then but, thankfully for the creation of a great song, she was left alone to wander the wide and empty pavements of Oxford Street.

She recalled: “I got thrown out and as I was running away the phrase ‘Chasing Pavements’ came to me so I sang it into my phone.” When she got home to the flat she shared with her mum, Penny, over the Co-op in West Norwood, south London, she made straight for her room and grabbed her guitar.

The song was born that would provide Adele with her important breakthrough in the US. By sheer fluke she performed it, in October 2008, on the most watched episode of US show Saturday Night Live for 14 years.

Her management had no idea when she signed up that she would feature alongside notorious US vice-presidential candidate Sarah Palin, also making a guest appearance.

Adele strongly disapproved of Palin’s opposition to same sex marriages and civil partnerships and refused to allow the politician in her dressing room. But she remembered to change “pavement” to “sidewalk” when she sang it. By the time she landed back at Heathrow after the show, 19 was already number one on the iTunes chart.

Adele, it was already clear, had the ability to describe universal and timeless emotions. Breaking up, it seemed, was always the most memorable part of a relationship and Adele had discovered the secret of her creativity. She wrote Rolling in the Deep as a “**** you” song to another ex with whom she had shared an apartment in Notting Hill. When she discovered he had become engaged, she wrote the melancholy Someone Like You. Her mum Penny cried when she heard it for the first time, describing it as “beautiful”.

The course of Penny’s life had changed forever when she had her beloved daughter. The same thing happened to Adele when she gave birth to her son, Angelo, in October 2012 aged 24.

She was in a settled and strong relationship with the boy’s dad, Simon Konecki, who she would eventually marry two years later. Simon was 14 years her senior, a larger-than-life Old Etonian and a divorced father to a daughter. He was a former investment banker and, superficially at least, not at all the sort of person to become romantically involved with Adele.

He did, however, share her Left-wing views while she admired his social conscience, deprecating sense of humour and a free spirit that mirrored that of mum Penny.

He was happier wandering around a pop festival in jeans than drinking champagne at the Savoy. He had abandoned his well-paid life in the City to start the charity that aimed to provide clean drinking water to communities in the developing world.

The pair met at a charity event in London when he was trying to gather celebrity support for drop4drop.

Adele did not announce her pregnancy until she had told family and friends – although that list did not include her father Marc Evans. They had fallen out when he sold his story to a newspaper and had, in her words, “****ing blown it”.

She told the world via her website that she was expecting in June 2012 then kept out of sight, giving birth to Angelo four months later. She did not reveal until much later that she suffered badly from postnatal depression, telling Vanity Fair magazine: “I was obsessed with my child. I felt very inadequate.”

Angelo became Adele’s world and she fiercely protected his privacy, making sure he would not become public property because of her fame. She admitted: “He has given me so much joy, so much purpose.”

She and Simon settled in Los Angeles in a palatial Beverly Hills mansion. In LA she didn’t feel such a hostage to her fame as she did in London. So she was furious when she was photographed by a paparazzo taking her eight month old son for a day out to the zoo in Central Park, New York.

They were sweet pictures but that wasn’t the point: this was a private family outing. She would eventually win a High Court legal action taken out in her son’s name against a picture agency that published photos of Angelo’s “milestone moments”.

Adele cancelled her final two live shows at Wembley in 2017 owing to throat problems and settled back into life in Los Angeles with Simon and Angelo.

She had once joked to the Sixty Minutes programme that she couldn’t write another break-up record, stating: “I’m madly in love and I don’t want to be like, ‘Baby, I’m sorry, we’ve got to break up. I’ve got a new album to deliver.'” Ironically, though, she and Simon did separate shortly after Adele turned 30 in 2018. She refused to go into detail, even in her recent Vogue interview, but did admit it was embarrassing and candidly admitted that her entire life had fallen apart and she had “****ed up”.

For a while she went off the rails, drinking too much and relying on her security to shepherd her out of LA nightclubs by the back door so that she wouldn’t be pictured stumbling out of the front.

But she and Simon kept their difficulties to themselves and have come out the other side. He lives opposite her in another grand property – she owns three in the Adele “compound” – so, unlike her own dad, he is not absent from Angelo’s life through geographical separation. Adele reconciled with her father – who had walked out on her life when she was just three and returned to his native Wales – a week before his death in May from bowel cancer, the same disease which claimed her beloved grandfather.

She had played him her new album on Zoom and told Vogue: “We actually got our peace.” She didn’t say whether Marc, who had upset her in 2011 with media interviews, had been introduced to his grandson.

She remains full of praise for Simon, stating simply that she chose the perfect person with whom to have her child.

Her new single, Easy On Me, was recorded for her son. When it is released on Friday, we will all have the chance to sift through the lyrics and examine the emotion and selfawareness of another classic Adele song.

Almost certainly it will be the biggest selling single of the year.

Adele is ready to face the world again but on her own terms.

She looks fabulous in Vogue – exactly a year after her friend Harry Styles wowed the magazine’s global audience with his groundbreaking cover.

She works out three times a day – a regime she says helps combat her anxiety – and has lost something like seven stone during the last two years. She also has a new man in her life, big time sports agent Rich Paul. He casually dropped in on her interview and was greeted with, “Hi darling”, staying just long enough to let the world know that they were a couple. Life in California clearly agrees with Adele but she remains a quintessentially British star, a national treasure lending her continued support to those affected by the Grenfell fire in her home town.

Down the road from her old home in south London is the florist where she bought flowers for her mum before she was famous. One of the young assistants told me: “I love Adele. She keeps it real.” It’s ok. She still does.

• Adele by Sean Smith (HarperCollins, £9.99)