McCartney milestone: Now he's 64

Stella's there today. Ringo too. Being Sunday morning, he may go for a ride. But it's his place in history that's on McCartney's mind. By Anthony Barnes

The most eagerly and lengthily anticipated birthday of any celebrity is finally here. No longer a case of "when"; today, 18 June 2006, Paul McCartney can actually sing "Now I'm 64".

But, as his relatives and closest friends gather for a party on the singer's estate in Peasmarsh, East Sussex, the world's leading popular musician must be wishing that when he wrote his famous song about old age, he'd made it 65 and not 64. For instead of this being a day when the world weighs his considerable achievements, it is one haunted instead by the allegedly seamy past of his recently estranged wife Heather, which he has told friends he fears will overshadow his musical legacy.

"He is, of course, deeply hurt because he feels he has been misled," one told The Independent on Sunday. "I think he is also genuinely shocked - as far as I know, he believed her when she had said the rumours that used to knock around about her past weren't true."

Yet Paul's children will rally round - after all, it is also Father's Day - and he will take it easy this morning after jetting in yesterday from a business trip in the US. After starting the day with a light breakfast of fruit, green tea and water, he will probably relax by saddling up one of his horses and patrolling the rolling fields around his farmhouse. In fact, that much of the song "When I'm Sixty-Four" ("Sunday mornings, go for a ride") will be accurate. Paul will later prepare for a family barbecue. Vegetarian, of course, and probably including some of the meat-free burgers from his late wife Linda's food range which he will cook.

His "nearest and dearest" friends will be welcomed. They will include Olivia Harrison, widow of the former Beatles guitarist George, and drummer Ringo Starr's wife Barbara Bach, as well as Paul's brother Mike. The red wine will be flowing - French is his preference - and towards the end of the day he will indulge himself a tot of Johnnie Walker whisky.

Paul is not a man known for his overindulgence. His drug experimentation in The Beatles days was fairly short-lived, although he did acquire a lifelong devotion to his daily spliff. His love of marijuana led to his brief imprisonment in Japan in the late Seventies, but also exposed cracks in his marriage to Heather. Although his smokes had been fine during his years with first wife Linda, who died of breast cancer in 1998, they were a constant source of irritation to his new wife whom he married four years later. He reluctantly agreed to give up the weed on her insistence.

Whether Heather, 38, will put in an appearance at today's party with their two-year-old daughter Beatrice is unknown. She is said to be keen to visit on such a special day; his family is not so encouraging. One friend said: "It is a tragedy that of all the times this could have happened in his life it is before his 64th birthday. I think there had always been the perception that after such a prolific, productive career, making music in the public eye for 44 years, that this birthday would be a time for everyone to reflect on the fullness of his life. But instead of assessing his achievements, it is now a case of assessing the wreckage. I really don't think he knew about the soft porn past. If he did he kept it bloody quiet."

During the past week he has visited New York for a pre-arranged business meeting, eating his breakfast in a Manhattan diner. Then it was on to Las Vegas to check out preparations for a new Cirque du Soleil show, Love, for which he had given permission for hidden Beatles recordings to be dusted off and used. "He's just been getting on with things and immersing himself in work. It is a business-as-usual approach. He has always tried to live a very private life away from the music business," said an insider.

Paul's older children - Stella, James and Mary, from his marriage to Linda, and Heather, his stepdaughter from Linda's earlier relationship - have long been wary and disapproving of his relationship with the former model. A friend said: "There has never been a photograph of the kids with Heather. I think that says everything you need to know about their relationship."

Stella was already comforting her father in public before the news about the marriage split had even emerged. The pair were seen having an intense heart-to-heart discussion while walking through Richmond Park in south-west London, just hours before the couple officially confirmed their separation. It was an abrupt end. Four years after they had married at Castle Leslie in Ireland's Co Monaghan, the couple issued a statement saying they were splitting "with sadness". They said it had become " increasingly difficult to maintain a normal relationship with constant intrusion into our private lives".

Friends and colleagues have been there for him. Ringo Starr - the man who sang "With a Little Help from My Friends" - said last week that he had been in contact and offered his support: "I just said 'I'm here if you need me'. That's all you can be. Break-ups are always hard." But for Heather, the support has been less intense. She has been largely demonised and columnists have been lining up to take chunks out of her reputation. Paul posted numerous messages on his website defending Heather in the days immediately after the separation, but even those have stopped. Their marriage is now in the hands of their lawyers. Sir Paul's and Heather's legal teams are now thrashing out a deal over custody of Beatrice and the share of his £825m fortune to which Heather will be entitled.

But Paul McCartney's career goes on. Instead of 64 being a prelude to retirement, he is making plans for a tour next year to swell his fortune further - far from the scrimping and saving his song predicted. His US tour dates last year raked in more than £40m. His creativity also goes on. Last year he released not only an album in his own right, Chaos and Creation in the Backyard, to the sort of critical acclaim he had not seen for years, but also an album of remixes with cutting edge producer Freelance Hellraiser, under the name Twin Freaks.

But it will be a poignant moment today when, four decades after asking in his song "will you still need me, will you still feed me?", there is no longer a partner around the answer the question.

Family Jewel: The story behind the song

Stuck for a time-filler during their Cavern Club days, the Beatles would knock out a jaunty instrumental to wallpaper the gaps caused by overheated amps and snapped strings.

The audience could have been forgiven if they struggled to spot the skiffle-driven tune, composed by Paul McCartney on his family piano, as a timeless classic. But nearly a decade after it was written, "When I'm Sixty-Four" was immortalised on one of the band's most iconic albums, Sgt Pepper's Lonely Hearts Club Band.

The lyrics looked forward to asking his love: "Will you still be sending me a Valentine, birthday greetings, bottle of wine?" The irony cannot be lost on him today.

The inspiration for those lyrics was Paul's father Jim, the man who instilled in him a love of music and bought him his first instrument, a trumpet, which he later swapped for a Zenith acoustic guitar. Jim was a keen self-taught pianist and trumpet player himself and led his own jazz ensemble, Jim Mac's Band, many years before Paul was born. Paul said: " He was my musical education. There was none in school - we never got music lessons. My dad was also a great crossword puzzle man and used to tell us kids to practise crossword puzzles - it would improve our word power. Having left school very early he'd had to educate himself. He taught me words that no one else knew and I was the only kid in my class who could spell 'phlegm'! "

Jim was a salesman at a Liverpool cotton exchange, which closed during the war years when he worked for an engineering firm producing aircraft engines, as well as working as a voluntary fireman. He later returned to the cotton exchange and worked there until his retirement.

Jim was still 56 when the piece was written by 16-year-old Paul, seated at the piano in the McCartneys' home in Forthlin Road, Liverpool. But by the time the band recorded the track, the first song to be recorded for the Sgt Pepper album, he was actually 64.

"It was all rather tongue in cheek," Paul said. "I wrote that tune vaguely thinking it could come in handy in a musical comedy. I didn't know what kind of career I was going to take back then." Indeed.

He must rue his unwitting gift to headline writers: "Will you still need me, will you still feed me, when I'm sixty-four?"