On the night of July 2, a transport chartered by Air Algerie took off from Algiers and landed in the small hours of the morning at Victoria, the village capital of the Seychelles Republic.

On board was an Algerian colonel. He was shepherding 18 tons of small arms for one of the world's tiniest nations. The package, delivered out of sight of all but a few of the 59,226 Seychelles residents, was big enough to provide one able-bodied male in four with an Ak47 Kalashnikov automatic rifle.

The officials who collected the secret shipment, howevers, almost surely limited the distribution to the new Seychelles Liberation Army, a force estimated at only 100 to 400. There is also a new People's Militia on the arehipelago but its devotion to the equally new president, France Albert Rene, is not yet certain.

This incident, related by an unimpeachable source, is one illustration of the remarkable transformation that Rene has effected in what had been one of the most relaxed members of the United Nations. Before Rene seized power, "security" consisted of several score police, armed with batons and old rifles safely locked in a shed.

Apart from the tuna that swim around the 86 coral reefs of the Seychelles, the place is of economically insignificant. But the islands lie off East Africa in the Indan Ocean and those waters have now become another zone of U.S.-Soviet competition.

For the first year after independence from Britain in 1976 the Seychelles were ruled, largely in absentia, by James Mancham. He is a playboy poet and politician who practiced nonalignment by simultaneously equiring a Yugoslav film actress and a British queen of the topless revue stage.

While Mancham was in London on pleasure and business in June 1977, Rene, his partner in an elected coalition, took power with 60 armed men. Their guns, supplied from Tanzania, were the first seen by most people there. The three persons they killed and a fourth who has "disappeared" were the new country's first political victims.

Rene is now in London, starting a three-day official visit that will take him to Prime Minister James Callaghan, Foreign Minister David Owen and, above all, Judith Hart, minister for overseas development or foreign aid.

It is unlikely that any member of the Labor Party government here will mention the shipment of Algerian arms or other weapons Rene has obtained. Neither London or Washington wants Soviet nuclear submarines using the Seychelles as a base and Rene has tirelessly repeated that this will not happen.

Moreover, both London and Washington do want to keep what the U.S. Air Force describes as a satellite tracking station on the main island of Mahe. Rene did throw out a couple of the station's U.S. civilians last May, claiming they had been plotting with Mancham. But Rene has made clear that the installation can remain.

"When you get down to bedrock," one Western diplomat explained, "the chap seems to be all right."

Rene, who comes here direct from another official visit to Paris, is in town largely to shake loose some of the money Britain has promised the Seychelles. On Independence, London lent on easy terms about $19.5 million - $330 for every man, woman and child.

Rene has developed projects using half this sum and wants approval for new ones, releasing more funds.

Why he has been filling his largely unpopulated islands with weapons baffles diplomats. One explains, however, "he has an obsessive fear of a counter-coup by Mancham."

So far, intelligence in London and Washington has detected no evidence that Mancham has made any plans to do to Rene what Rene did to him The Seychelles' first president lives stylishly here and has more of a reputation for recruiting complaisant women than mercenaries.

While Rene was away in China and North Korea last spring, his ministers claimed they had discovered arms caches for a pro-Mancham coup. They jailed 20 persons without trial, but Rene later freed them. Africa experts here speculate that Rene sought the July shipment from Algeria to protect his interests at home during his absence in Paris and London.

Rene took power in the name of democracy, claiming Mancham had proposed to him that they agree to put off for five years elections scheduled for 1979. The new president, described as a "pragmatic socialist" by admiring Western diplomats, tore up the constitution, rules by decree and promises to hold those elections based on a new fundamental law. His Seychelles People's United Party is a certain winner.

As President Rene explained in an interview this week with Le Monde:

"I am for the single party because it is necessary at any price to avoid everything which will divide us."

Rene has tried to take over te archipelago's muddled transport, has promised free schooling for nine years and abolished private schools, and has pledged free medical care.

So far, however, the evidence indicates that he has delivered more guns than social justice.