Sir John Compton, who has died aged 81 following a stroke, became prime minister of St Lucia for the third time last December, at the head of the United Workers party, which he had founded. He was the dominating political figure of the eastern Caribbean island for more than half a century - both before and after St Lucia's independence from Britain in 1979 - first as a member of the legislative assembly, then as chief minister, premier and, finally, prime minister.
Compton was typical of a generation of Caribbean politicians whose careers were launched on the back of anti-colonial sentiment, but whose pragmatism made them essentially conservative leaders. During his career, in a trajectory familiar to small Caribbean islands, St Lucia changed from a neglected, semi-feudal backwater with a large, depressed peasantry into an independent state that saw tourism displace agriculture as the economic driving force.
"Daddy Compton", as he was known, was a small, energetic man, born on Canouan, a tiny, bone-dry island, part of St Vincent and the Grenadines, south of St Lucia, and the home of his mother. He arrived in St Lucia as a teenager and was brought up by his uncle, a master mariner and successful businessman from the east coast. The fact that Compton was not by birth a St Lucian was sometimes held against him, as was the fact that his parents were unmarried.
He was educated at St Mary's Academy, the island's best school (a later pupil was Derek Walcott). Like many islanders in those days, he worked for a spell in the oil refineries of the Dutch island of Curacao. He then studied law at the London School of Economics, was called to the bar at Gray's Inn in 1951, and in the same year returned to St Lucia, where the process of self-determination was evolving with the introduction of universal suffrage.
Compton set up in private practice but soon entered politics, becoming an independent member of the island legislative council in 1954. He represented Micoud-Dennery, a country district with ailing sugar estates, away from the urban centre of the capital, Castries. Two years later, he joined the island's first mass party, the St Lucia Labour party (SLP), becoming deputy leader (1957-61) under his mentor, the trade unionist George Charles. Compton made his first important intervention into anti-colonial politics in 1957 when the island's sugar factories, a major employer, refused its workers union recognition. The union launched a strike. Compton entered the dispute when, arriving at a factory, he was confronted by its owner with a gun. In response, Compton drew his own gun.
As the crisis escalated, the British government, overreacting, sent a warship and police reinforcements from neighbouring islands. The strike ended with the workers getting a pay rise - and union recognition. Compton was charged with disturbing the peace, convicted and fined, but he emerged a hero. By the early 1960s, however, he had resigned from the SLP, frustrated by the old guard, and in 1964, formed the United Workers party (UWP): that same year the UWP won the island general election and Compton became chief minister, with more than 92% of the vote in his own Micoud-Praslin constituency. In 1969 and 1974, he triumphed again, and on independence, in February 1979, became prime minister.
That July, however, despite the euphoria of independence, Compton was dethroned: in the face of a well-organised opposition, he lost the general election. He was accused of losing touch with the grassroots, and failing to deal with urban drift and growing unemployment.
But he was back in power in 1982 - and remained there until 1996. Under his leadership, St Lucia began to develop. Bananas - the replacement for sugar that had faded out by 1961 - started their "green gold" years, in which thousands of small farmers benefited from the protected market in Europe. Agriculture in the central and east parts of this mountainous island, marble-halled hotels in the north and an (unsuccessful) attempt to generate foreign investment in a free-trade zone in the south were all part of Compton's plan. There were more jobs, even if they were unskilled. The infrastructure was improved and schools were built in rural areas. In 1992, in what he called his "rendezvous with destiny", Compton won another election. The voters were unmoved by newspaper stories about his alleged relationship with a teenage girl, or by criticisms of a high-handed administrative style.
More importantly, however, banana prices began to fall, and in 1993 disaffected banana farmers went on strike. Two farmers were killed in a confrontation with police. Compton, this time in opposition to the strikers, spoke of having to face an angry mob in the eastern Mabouya valley, "an area which has benefited so much from my work and personal sacrifice". Himself a wealthy banana and coconut farmer, he was proud that he drove around the island in his "humble pick-up". But during the strike, the truck was stoned.
In foreign affairs, Compton had supported the 1983 US invasion of Grenada, and was less enthusiastic than many Caribbean leaders about relationships with Fidel Castro's Cuba. He was, however, an energetic proponent of regional integration projects, such as Caricom, the Caribbean's own, though underdeveloped, common market, and backed the Organisation of Eastern Caribbean States and, unsuccessfully, a federation of the Windward Islands.
A year after Compton resigned the party leadership in 1996, the UWP lost the general election, and in 2001 he was back, having teamed up with another veteran, the leftwing George Odlum, to "protect his legacy". This liaison collapsed, but last year Compton was once again back in power, after soundly beating the younger, more modern, Kenny Anthony, of the St Lucia Labour party. One of his first policies was to establish diplomatic relations with Taiwan, and ditch Beijing, a move that was seen as a retrograde step. Ill-health forced him to resign in May.
Compton had overseen the political evolution of his country; as one islander said, "The man who build the oven, let him cook the bread." He is survived by his wife Janice, one son and four daughters.
· John George Melvin Compton, politician, born April 30 1926; died August 7 2007