FOR Cat Stevens July 11, 1980, was the day the music finally died. It died because he killed it. He killed it because his new-found religion, Islam, forbade it. Or so he thought at the time. After returning from a pilgrimage to Mecca, he sold all his instruments and his gold records, donated the proceeds to charity, and swore that he would never sing again.

But it was a mistake. He was wrong. And now, more than 20 years later, he has acknowledged that he was wrong. This week, for the first time, he admitted that, upon reflection, he had made ''a few mistakes''. It happens sometimes, especially when you embrace a faith with the unconditional zeal of the convert. ''Music in Islam is a grey area,'' he said in an interview. ''There were some who were advising me

that it was forbidden - but the reality is that you find music everywhere in the

Muslim world.''

After a lengthy period of measure and maturity, the former pop star, who changed his name to Yusuf Islam, has at last come to terms with the music he lost faith in after his conversion.

''Looking back at how much my music meant to me and to others, I certainly don't belittle that,'' he says now. ''It has taken me a while to get an understanding of the place of music in the spiritually directed life.''

This is not to suggest that Cat Stevens is once again alive and well and preparing, at the age of 53, to re-establish himself on the music scene. No, to all intents and purposes, Cat Stevens is dead. But there is a small part of his heart still beating in Yusuf Islam. Enough to motivate him to perform in the recent Concert For New York City, contributing a very moving, acapella version of his song, Peace Train.

And enough to persuade him to take a tentative, almost reluctant, step back into his past to oversee the making of a four-CD boxed set of his recordings, released this week. All his royalties from the project will go to charity, half to the September 11 fund to help victims of the terrorist attacks.

In an accompanying essay to the set, he recalls his own remarkable journey from darkness to light; from the pop excesses of drink and drugs, through his rejection of ''sin and greed'', and finally to the peace of mind he gained through religion.

He was born Steven Demetri Georgiou, the youngest of three siblings, in Soho in 1948. His Greek Cypriot father and Swedish mother ran a restaurant, the Moulin Rouge, in Shaftesbury Avenue, and the family lived in a small flat upstairs. Like the song, he has, it seems, always been on the road to find out. Even as a child his spiritual identity was unclear to him. His father was strict Greek Orthodox while his mother came from a Baptist background. The young Steven went to a Roman Catholic school in nearby Drury Lane.

With the swinging London of the sixties as his playground, it was not surprising that he took an early interest in pop music. Early influences came through his sister Anita's collection of Sinatra and Gershwin records, and his brother David's interest in the Everly Brothers and Buddy Holly.

When The Beatles arrived in 1963, the 15-year-old Steven persuaded his father to buy him a guitar and, after a half-hearted attempt at forming a group, he decided to embark upon a solo music career.

In July, 1964, while still a student at Hammersmith Art College, he made his first public appearance at the

campus pub, the Black Horse. By then he had adopted the name Cat Stevens (because a girlfriend had told him he had eyes like a feline).

The following year he and his brother hawked his songwriting work around Denmark Street and eventually secured a publishing deal. One of the first songs he sold - for (pounds) 30 - was The First Cut Is The Deepest which, two years later, would be a huge hit for P P Arnold (the first of many performers to record the song over the past 35 years). Another was Here Comes My Baby, which was a hit for the Tremeloes.

Cat Stevens's recording career didn't start until 1966 when producer Mike Hurst took him under his wing and signed him to Decca's trendy new Deram label. His first single, I Love My Dog, reached number 28 in the charts. Interestingly, he now admits that he ''pinched'' the melody from a song by World Music performer Yusuf Lateef. After becoming a Muslim he decided to right the wrong, confessing his crime to Lateef and arranging for royalty

payments to be made to him.

It was the follow-up single, Matthew and Sons, a classic pop song in which Dickens meets Carnaby Street, which effectively launched Cat Stevens's career, reaching number two in the charts.

His popularity soared and, still a teenager, he embraced all of the hedonistic pleasures which the pop world had to offer. Then in February 1968 came the illness which marked the defining moment in Stevens's life. It began with a nagging cough, dismissed as the result of too much drinking, smoking, and fast living.

But his condition worsened and, shortly after his 20th birthday, he was diagnosed as suffering from tuberculosis. It was a life-threatening ailment. He spent three months in hospital and a further nine weeks recovering at home. During that period he took stock of his life.

''I became aware of my own mortality and the inevitability of death. A lot of important questions came into my mind. It was a very important stage of my life,'' he said.

It was an infinitely more grown-up and reflective Cat Stevens who emerged, fully recovered from his

illness. He dabbled in Buddhism

and became part of the love-and-

peace movement. The 11 albums he recorded over the next eight years charted the journey of a troubled

soul, a man in constant search of an answer. He abandoned mainstream pop. His songs became deeper, more personal, more searching. He started designing his own album sleeves, painting in the naive, simplistic, eastern European style.

Now signed to the Island label, Mona Bone Jakon was the first in a series of folk-influenced albums destined to find their way into every self-respecting bedsit. It was followed by two

hugely successful works, Tea for the Tillerman and Teaser and Firecat.

Cat Stevens was the

master of the solitary songwriters, disclosing his private thoughts, aspirations, and desires through achingly beautiful songs such as Wild World, Father and Son, Lady D'Arbanville, and Moon Shadow.

His search for inner peace continued. He became reclusive. After being on tour, playing to crowds of 40,000 in huge sports stadiums across the world, he would seek refuge in the solitude of his lonely flat in Rio de Janeiro where he lived the life of a

millionaire tax exile.

Then in 1976 two things happened which altered profoundly his perception of life. While swimming off the coast of Malibu in California, he feared he was drowning. As a strong tide threatened to sweep his body too far from the beach, he shouted: ''Oh, God! If you save me I will work for you!'' Suddenly, a wave came from behind and pushed him back to safety.

It was, he says, a moment of truth. Not long after that incident his brother David bought him a copy of the Koran for his 28th birthday. Until then he had courted just about every religion - but not Islam. This he put down to a kind of inbred anti-Muslim hostility inherited from his Greek Cypriot roots. But he read the book with an open mind.

The following year, on a Friday morning in winter, he walked to the mosque in London's Regent Park to declare his new-found faith.

Cat Stevens continued to make music - for a while, at least. But he found it increasingly difficult to keep on the straight path while working amid the hype and the commercialism of the rock music industry. And, after that

pilgrimage to Mecca in 1980, he renounced his former life and assumed his new name.

Since then he has worked tirelessly for Islam, becoming a high-profile spokesman for Britain's Muslim community. He lives in a modest semi-detached house in Willesden with his wife, Fouzia Ali, and four children. His eldest daughter, now 21, was recently married in a union arranged by both sets of parents.

He has used the considerable proceeds from his music career to establish four single-faith Islamic schools in north London. Four years ago one of them, Islamia primary, became the first Islamic school to join the state sector.

His once-extreme views have certainly mellowed over the years. When the controversy over the author Salman Rushdie's novel The Satanic Verses erupted in 1989, Yusuf Islam was still a relatively recent convert to Islam. Headlines, reading ''Kill Rushdie, says Cat Stevens'' appeared in the tabloids, causing angry reactions from both fans and musicians. The American band 10,000 Maniacs even removed their version of Peace Train from one of their albums in protest.

The artist formerly known as Cat Stevens later explained that, as a high-profile Muslim, he had simply been invited to join a letter campaign requesting the publishers to think again. ''They ignored the plea. Suddenly the media tried linking me to supporting the latest fatwa. The fact is I never supported the fatwa,'' he said.

Last year Islam was denied entry to Israel and deported within hours of arriving. No reason was ever given for the action, but it was thought to have been connected with claims that, during a previous visit to the country in 1988, he delivered funds to Hamas, the militant Islamic group.

Yusuf Islam strenuously denied this, issuing a statement that he had ''never knowingly supported any terrorist group - past, present, or future''.

He was extremely vocal in his condemnation of the September 11 bombings in New York and Washington, saying that it was his duty as a

Muslim to make clear that such orchestrated acts of ''incomprehensible carnage'' had nothing to do with the beliefs of Islam.

The new CD boxed set (in which, it's worth noting, he contributes a brand new song) is his way of kissing and making up with the loyal fans he left behind all those years ago. As he says: ''I've managed to make peace with my past, as it's making peace with me.''