ST. JOHN'S, ANTIGUA -- One of the hemisphere's most durable leaders, millionaire Prime Minister Vere C. Bird Sr., has dominated politics on this sun-washed eastern Caribbean island for all but five years since World War II.

The 80-year-old leader is rarely seen in public these days. Rather, the spotlight has shifted to his two older sons, who control most of the key government ministries with their father's blessing.

For years it was widely assumed that one of the sons would take over when the prime minister, known as Papa, died or retired. The succession intrigue has been spiced by scandals involving misspent public money and the shifting allegiances of political rivals, and, not least, by Papa Bird's 27-year-old mistress, known to one and all as "Cutie," who has been at his side since she was an eighth-grade beauty queen in 1978.

Papa Bird was elected last year to his sixth five-year term, and most of Antigua's 78,000 people seemed blithely unconcerned by the brothers' jockeying for power while the economy hummed along at 7.5 percent annual growth and almost full employment.

But this April, an international arms scandal erupted that suddenly threatened the Bird dynasty and even the tourist trade that accounts for three-quarters of the island's economy.

The scandal, involving the transshipment of Israeli weapons to one of Colombia's most notorious drug barons, has rattled the country's business community, worsened relations between Bird's two older sons and disrupted island politics.

"It's time for us to move away from the days of the Birds," said education minister Reuben Harris, a member of the Birds' own Antiguan Labor Party. "The government now is characterized by corruption."

"It's become clear that it's a free-for-all here," said Baldwin Spencer, who holds one of the two opposition seats in the 17-member Parliament. "There's no accountability, no ethics in government. The Birds all do as they please."

Several thousand Antiguans marched in protest against the government and the arms scandal last month, and signs and bumper stickers have started appearing around the island announcing, "I'm against gun-running."

A commission of inquiry headed by a prominent British jurist, Louis Blom-Cooper, is to begin hearings into the affair July 16 and is expected to make its report to the prime minister by October.

The scandal involves a shipment of 400 Galil assault rifles, 100 Uzi submachine guns and thousands of rounds of ammunition from Israel, ostensibly consigned to Antigua's 80-member defense force. But the arms were never unloaded on the island.

It appears that as soon as the arms arrived here April 23, 1989, they were transferred to another ship and rerouted to Colombia. In February, Colombian authorities discovered nearly 200 of the Galils on the ranch of Medellin drug cartel kingpin Gonzalo Rodriguez Gacha, who was killed in a December shootout with Colombian police.

It is not the first weapons scandal here. In 1981, a company called Space Research Ltd. began testing large-caliber arms in Antigua, sparking an uproar in the predominantly black island when it was revealed that the firm was exporting to South Africa. The head of Space Research, Canadian Gerald Bull, moved on and was found shot to death in Brussels three months ago.

A key figure in the latest case is a retired Israeli lieutenant colonel, Yair Klein, who is now a private security specialist and under indictment in Israel. Klein has said the arms were originally intended for a planned paramilitary base in Antigua that was to train Panamanian exiles to overthrow former Panamanian strongman Manuel Antonio Noriega.

While the base was never approved by Antigua's government, the arms were shipped from Israel, addressed to the Antiguan government.

The main questions in Antigua are: Who approved the order for the weapons? Why was it approved? And how did the arms end up being transshipped to Colombia?

Attention has focused on Vere Bird Jr., 53, the prime minister's oldest son and a government minister until he was forced to resign when the scandal broke in April. His signature appears on a document sent to the Israeli government authorizing the weapons shipment and guaranteeing that the arms were intended for Antigua's exclusive use and would not be forwarded to a third party.

There have been suggestions, but so far no proof, that Vere Bird Jr. received a substantial payoff, perhaps from Klein, in return for authorizing the arms shipment. A report in New York's Newsday, citing Colombian intelligence reports, said that an unnamed Antiguan "high-ranking official offered to help in return for a payoff of $125,000."

Vere Bird Jr. has denied any knowledge of the affair, and said that his signature on the document is a forgery. In a brief interview on the doorstep of his home last week, he said: "One can only tell my side of the story if there's a story to be told."

Vere Bird Jr.'s chief antagonist is his younger brother Lester, 52, who is deputy prime minister, foreign minister, minister of economic development and minister of trade, tourism and energy.

The two men have long been rivals. While Vere Jr. is widely seen as a kind of affable slowpoke, unpolished but down to earth, Lester is a bluff, commanding presence who was once a champion long-jumper at the University of Michigan.

These days, Lester lives in a modern mansion atop a hill overlooking the sea, while Vere Jr. lives in a ramshackle house badly in need of a coat of paint. Both men are millionaires, British-trained lawyers who have been accused of exploiting their public positions for profit in private development projects.

Lester Bird's aggressive stance in the Israel-Colombia arms affair -- he has made key documents public before sharing them with the cabinet and has hired Washington attorney Lawrence Barcella, a former federal prosecutor, to investigate the matter in Israel -- has been interpreted as an effort to quash his brother's political career.

Lester Bird acknowledged in an interview that his relationship with his brother has become "strained," but denied any political motive in his pursuit of the arms case.

"I am not an enemy of my brother," he said. "But we all take certain positions and have a social contract with the people of the country and a fiduciary responsibility. . . . This is in no way intended as a witch hunt to get Mr. Vere Bird Jr."

Lester Bird said he would insist that his father release the report of the commission of inquiry when it is completed this fall.