The British government reversed itself yesterday and announced that it will allow the 130,000 persons -- most of them Americans -- who bought cut-rate transatlantic tickets before the proposed fares for the winter season were disapproved to use them.

"I want to leave the passengers out of this. This is not a row about passengers. We don't want to harass them," said British Transport Secretary Nicholas Ridley in announcing the government action.

The government, which said it was incensed that 13 airlines continued selling the low-cost winter tickets even after Britain disapproved the new fares on Oct. 18, took the unprecedented step last Thursday of invalidating all 130,000 tickets. That action, which was disavowed yesterday, would have forced everyone holding cut-rate tickets to pay more money for the flights.

The winter fares were supposed to take effect Thursday and run until March 31.

The British action last week threw the already complicated transatlantic flight picture into disarray and disrupted plans of travel agents, airlines and passengers in the United States and Great Britain. The widespread effect on the traveling public of last Thursday's order appeared to play a major role in Britain's decision yesterday to allow passengers to use already purchased cut-rate tickets.

Nonetheless, the British announcement specified that those who bought about 7,000 tickets between the time the new fares were disapproved and last Thursday, when airlines were ordered to stop selling those tickets, will have to pay a higher rate for their flights.

"I think it was reprehensible for the airlines to go ahead selling even after our announcement," Ridley said. "It wasn't until we disallowed the fares sold previously that they took us seriously" and stopped selling tickets.

"In light of that and in order to cool the situation and to cause a minimum of disruption to passengers, I have decided to allow those low-fare tickets sold until our announcement Oct. 18 to be honored," he continued.

Despite the Ridley order, three major airlines flying the Atlantic -- Pan American, TWA and British Air -- said they would honor low-cost tickets sold through Thursday and face the consequences of their actions from the British government. If Britain presses the case, the carriers could face fines for selling tickets at an unauthorized low fare, airline officials said.

"We wish we could offer the cut-rate tickets to more people, but we're glad we don't have to go through the confusion at the airport" of collecting extra fares, said Sally McElwreath, director of corporate communications at TWA. She said TWA encouraged passengers to hold on to their tickets in the hope that Britain would change its mind.

The United States already had approved the low winter rates. Britain, however, refused because it said it could not get assurances from the U.S. government that the cut-rate fares would not be used in future antitrust suits in the United States. This was seen as a major escalation of Britain's long-running battle against the extension of U.S. antitrust laws to British airlines flying the Atlantic.

The liquidators of Freddie Laker's bankrupt Skytrain service already have a billion-dollar antitrust suit pending in U.S. District Court in Washington, and a federal grand jury has been conducting a year-long investigation of possible criminal antitrust violations by airlines flying the lucrative Atlantic run. Richard Branson, chairman of Britain's new low-cost airline, Virgin Atlantic, has accused the major carriers of adopting the lower fares to drive him out of business. He told the Associated Press that he would file an antitrust suit similar to Laker's if Britain approved the new low fares.