A freewheeling era of casino gambling in London, symbolized by scantily clad bunnies spinning the roulette wheels at the popular Playboy Club on Park Lane, comes to an end tonight when the Playboy casino is closed by its new owners.

There were tears when the bunnies were told earlier this week they would be phased out even if the Trident organization, which now owns the Playboy casino, succeeds in securing a license to reopen it with a new name and image in May.

Legalized gambling will be far from dead in London, which during the 1960s and 1970s rivaled Las Vegas as a casino mecca for high rollers, particularly from the oil-rich Middle East. There are still 16 casinos left here and more than 100 others in the rest of Britain, plus thousands of licensed betting shops and bingo parlors.

But the most flamboyant operators of London's largest casinos are gone, forced out by police and Britain's Gaming Board for extending credit and offering other inducements in competition for a declining number of big spenders. In less than two years, 10 London casinos were taken away from three major operators: Playboy, which took in a sixth of all the money spent at the tables in London each year; Ladbrokes, once Britain's largest gaming operators, and Coral Leisure Group.

Trident, a British commercial television company, bought a group of casinos and betting shops here from Hugh Hefner's beleaguered Playboy empire late last year after Playboy was refused renewal of its licenses for two London casinos because of alleged gaming law violations. The Gaming Board's decision to allow Trident to apply for new licenses for the two casinos--the Playboy Club and the smaller, more opulent Clermont Club--is seen as a sign they will be granted.

But the bunnies, with their scanty outfits, velvet bunny ears and fluffy white tails, will disappear with the Trident closing of the Playboy casino temporarily at the end of gambling late tonight. Half of the staff of more than 600 are being laid off and a new look in both decor and decolletage is planned for the casino's intended reopening.

"We are looking at ideas for new uniforms" for waitresses, dealers and croupiers, a Trident spokesman said. "There will be a bit of a cover-up."

A senior Trident executive said long gowns, with transparent sleeves to avoid allegations of cards being hidden in them, are being considered. This way, he said, women with the intelligence and dexterity to make good dealers will no longer be refused jobs because "they have the wrong kind of legs."

"It really is an end of an era," the executive said. "The bunny girls are associated with an image we want to avoid. They're passe these days when we've got a woman prime minister . . . ."

The successful challenge by police to Playboy's casino licenses included allegations, denied by Playboy officials and staff, that some wealthy customers were attracted by the after-hours company of some bunnies. The American who ran Playboy's gambling interests here until the license challenge, Victor Lownes, was Britain's highest paid executive, held lavish parties at his country mansion and lived with a well-known Playboy magazine centerfold model.

Trident is trying hard to impress the Gaming Board with its comparative staidness, as well its dedication to strict observation of gambling regulations and vigilance against corruption. It has given primary reponsibility for this to Peter C. Neievens, a former deputy assistant police commissioner at Scotland Yard who was hired as a director of Trident's new gambling division.

Britain's gambling laws permit almost any form of betting in licensed establishments, but forbid such inducements as gifts or the serving of alcohol in casinos. Yet the odds in British casinos favor gamblers more than anywhere else, and this appears to attract big bettors.

Despite severe recession and an apparent thinning of high-rolling visitors, the total take of a smaller number of British casinos last year fell only slightly, to about $1.2 billion.

Playboy's casinos here earned more than $30 million before taxes last year, making their sale to Trident, for somewhat less than that amount, a bargain, and their loss a major blow to Playboy. Only a standard Playboy Club remains next door to the casino. It is being run under franchise by Trident, which has not yet decided its future.