But at first these were not especially positive for Coxsone Dodd and his recording company. In this he was not alone: most of the island's labels had been caught napping by the sudden achievement in 1970 of his longstanding rival Duke Reid's Treasure Isle label's great success with U-Roy, the first deejay to significantly break through as a recording artist; that year U-Roy had the top three tunes on the Jamaican radio charts, voiced over rocksteady rhythms. An entirely new genre had emerged, one that went hand-in-hand with the sound of dub, and the 'versions' that began to appear as the B-sides of 45rpm singles, ubiquitous by the middle of the decade. These two elements changed first music in Jamaica and then music around the world forever.

At the start of the 1970s, the regular Sunday auditions continued to be held in the Studio One yard; meanwhile, on that day the studio itself would be recording gospel tunes for Mr Dodd's Tabernacle label.

But the anarchic nature of deejay music and dub signified a backyard creativity that was of a far more roots orientation. So it came as little surprise that in the 1972 Jamaican elections the left-leaning People's National Party (PNP), under Michael Manley, defeated the conservative Jamaica Labour Party's (JLP) incumbent Prime Minister Hugh shearer. Like a Biblical prophet, the now Prime Minister Manley - who was nicknamed Joshua - would stride forth waving aloft his 'rod of correction'. Arguing not unreasonably that it made absolute sense for developing countries to ally with each other rather than with superpowers. Manley forged a close relationship with neighbouring Cuba, and nationalised the local bauxite industry (which supplied the raw constituent of aluminium), which brought down on Jamaica the wrath of the United States. Michael Manley remained in power until 1980, by which time - notwithstanding the efforts of Bob Marley to end the violence through the Peace Concert in 1978 - the island was being torn asunder in an undeclared civil war.

At first Manley also threatened to legalise ganja; but soon he backtracked on this, bringing in an American task force to attempt to eradicate the 'herbs' trade, in the circumstances a politically schizophrenic decision that only emphasised the confusion beginning to beset the nation.

You imagine that this US drugs task force had no great reason to visit 13 Brentford Road, the downtown Kingston home of Studio One. But if they had they might have hit a rich seam of marijuana. Whereas Duke Reid, a former policeman, forbade herb consumption at sessions for Treasure Isle, the more benign man-of-the-people who was Clement 'Coxsone' Dodd had no issues at all with any fondness of his musicians for marijuana: indeed, it was one of the principal attractions of Studio One for many of them, especially those who attracted to the faith of Rastafari, burgeoning since the visit to Jamaica in 1966 of His Imperial Majesty Haile Selassie I, the ruler of Ethiopia, and now taking a quantum leap amongst not only Jamaicans everywhere but increasingly on most other Caribbean islands.

Interlinked with this wider fascination with Rastafari was the cultural roots music scene, which ran as counterpoint to the deejay movement even though it was infrequently interlinked with it. Cultural reggae, for which Studio One became a standard-bearer, slowed down the faster style of reggae that had emerged as the new Jamaican pop music at the end of the Sixties; its purest expression and subject-matter came from Winston Rodney, the man from St Ann's Bay on the Jamaican north coast known as Burning Spear, who recorded his utterly unique, and almost wilfully uncommercial, songs of faith and praise for Studio One from 1969 to 1974. 1973's 'Studio One Presents Burning Spear' and 'Rocking Time', released the next years, contained most of the material recorded at Brentford Road by Spear; by the end of the twentieth century he had become undisputedly Jamaica's elder statesman of music. Studio One, he told me not long after he left the label, was "the University of Jamaican music".

Also recording at the label in the early 1970s was another Rasta vocalist, Horace 'Sleepy' Andy; a Kingstonian with a striking falsetto voice who greatly influenced subsequent Jamaican singers. In 1972 he recorded 'Skylarking', the tune for which he best known, but all of his output was of a similar high standard. Meanwhile, during the first half of the decade The Gladiators, led by Albert Griffiths, held sway at the label as a cultural act in the great Jamaican tradition of the male vocal trio. This was timely, for the Heptones, who had fulfilled this role at Studio One from 1966, with their 1968 'Heptones On Top' album proving one of the most Jamaican LPs ever, had for a myriad of reasons left Coxsone in 1971. Leroy Sibbles, whose pure vocals had led the trio, had also supplied many of Studio One's signature basslines, as well as arranging much of the Brentford Road material. His departure was a loss, though time permits it to be seen as part of the evolution of the label, an adaptation to a changing era: as the decade progressed Mr Dodd upped the Brentford Road studio from eight-track to sixteen-track and finally to a twenty-four track facility. The in-house session group at Studio One, meanwhile, was now the work of The Soul Defenders, led by Jah Privy, a guitarist with a country feel to his picking; Earl 'Bagga' Walker, who had worked with Studio One's Sound Dimension, was the Defenders' bass-player, whilst the redoubtable but volatile Leroy 'Horsemouth' Wallace played the drums. The horn section was led by the veteran Vin Gordon; David Madden was on trumpet; and the legendary Cedric Brooks, a Studio One veteran, was the sax-player. The Soul Defenders first played on a pair of cultural tunes, Horace Andy's 'Skylarking' and Freddie McKay's 'Picture On The wall'. But the incomparable Studio One stalwart Jackie Mittoo, who by the age of fifteen had been playing with The Skatalites and whose keyboard-playing had helped create the sound of reggae, quit the island in 1975 to live in Canada, where he set up a studio; during his frequent trips to Jamaica, however, he continued to contribute to Studio One recordings.

In the mid-1970s Cornell Campbell, formerly a member of The Uniques and The Eternals who had started recording ska-based tunes for Studio One in the early 1960s, became a cultural singer at Brentford Road, for which his distinctive, Curtis Mayfield-tinged falsetto was amply suited.

When Lincoln 'Sugar' Minott arrived at Studio One around the same time, initially as one of the African Brothers, he was taken up by Coxsone Dodd as an in-house vocalist and musician. Taking a cue from the deejays of the time, many of whom had learned their craft toasting over Studio One 'versions', he began to record using backing tapes from the 1960s found in the Brentford Road vaults, rather than employing a live band. The singer's innovation set the scene for the creative rebirth of Studio One during the second half of the decade. Soon he was joined in this pursuit by vocalists such as the gifted Freddie McGregor and the versatile Johnny Osbourne.

By the end of the 1970s, Studio One was experiencing a renaissance. This recycling of rhythms by leading singers marked part of the shift into dancehall, emphasised when Coxsone started to put out cultural deejay tunes, like those of the very original Lone Ranger. A rougher-edged toaster, influenced by Tappa Zukie, it was Lone Ranger who introduced what became such staple vocal punctuations of the trade as "ribbit"; at one time in 1980, Lone Ranger had five tunes in the Jamaican Top 10, even appearing as part of a show at Madison Square Garden.

Meanwhile, both the deejay combination - another Studio One innovation - Michigan & Smiley and the cultural vocalist Willie Williams employed to great effect the 1966 rhythm of 'Real Rock' on, respectively, 'Nice Up The Dance' and 'Armagideon Time'; the tunes marked a triumphant return to form for Studio One, celebrated on a Disco 45 that ran together both of these 'Real Rock' developments. It was a fitting conclusion to the difficult decade of the 1970s, a time of great strife in Jamaica, but one which 'the University of Reggae' proved to have successfully weathered.