A two-day rail strike, the World Cup soccer matches in Spain, the Wimbledon tournament and the Henley Regatta provided ample distraction last week for those Britons not mesmerized by the birth of a royal heir.

Overall, it is a happy summer for Britain. And the normal annoyances have been made somewhat less disturbing, the traditional pleasures of sport and the monarchy made even more joyful, by what has come to be called here "the Falklands factor."

A combination of political, military, economic and spiritual changes arising from an unexpected war half a world away, it is quite unlike anything that has happened to Britain since the disastrous Suez crisis became for Britain what Vietnam was later to become for the United States.

The failed 1956 Anglo-French-Israeli attempt to take the Suez Canal back from Egypt's radical new leadership sent Britain into a long period of retrenchment, speeding the dismantling of the empire and the withdrawal of troops from most outposts. At home, governments of the left and right tried, with an equal lack of success, to cope with increasingly severe economic problems.

No one here seems to believe seriously that the Falklands will change the realities of Britain's reduced place in the world. But Britain's success at mobilizing a naval, air and infantry task force and sending it 8,000 miles to challenge the Argentine military, practically on its home territory, has upended the belief of many that the British could no longer reach ambitious military goals.

A senior aide to Prime Minister Margaret Thatcher argued that the Falklands victory dealt a blow to corrosive defeatism on the home front as well.

Among the questions Thatcher now faces is whether this transitory triumph can somehow be translated into new vigor for an economy that is still a long way from booming. Can the "Falklands factor" help Britain be more comfortable in its role as a post-imperial power? Perhaps most important for the viability of the current government, will Margaret Thatcher win a place among the century's great prime ministers, or will she return to the rolls of the worst, where polls put her a year ago (12 percent lower than even Neville Chamberlain)?

What emerges from dozens of conversations with persons representing a broad spectrum of British thought is a sense that Thatcher has earned an extraordinary opportunity. To take advantage of it, experts here say, she will have to parlay luck, skill and leadership.

For the short term, at least, Thatcher's popularity has soared. As recently as March, polls showed her staying barely even with her combined political opponents. Today, she would win a resounding victory. Public satisfaction with her handling of the Falklands crisis is 84 percent. Perhaps most important of all, more than 70 percent of those questioned by the respected polling organization Market Opinion and Research International said continued sovereignty over the Falklands justifies higher taxes to meet the cost of maintaining military forces there.

In the government's first post-Falklands showdown with the troublesome government workers' unions, Thatcher easily held her ground. She adamantly refused to bend to railway workers angry over productivity issues and backed British Rail management, which said it would take a three-month strike. Now, the railroad engineers are promising to strike. Again Thatcher has refused to give in under pressure.

"The trade unions would like nothing better than to come in here for beer and sandwiches and run the country," one Thatcher aide said. "Well, it's just not going to happen."

Despite the improvement in the inflation rate, signs that the recession is ending have grown weaker again. The Bank of England reported last week that the output of British industry has been steady since last fall, although it predicted an increase for the rest of this year. The bank said that the rate of growth in productivity had slowed again after a spurt, and the government reported that the real disposable income of families is stuck where it was a year ago.

The Falklands crisis and the labor disputes illustrate the same pattern in Thatcher's leadership. She has demonstrated time and again that she will not be deterred from pursuing stringent policies on the domestic scene anymore than she would back away from the risks of a military campaign on the other side of the globe.

There are a host of examples. Last year, Thatcher refused to negotiate with Irish Republican Army hunger strikers over prison conditions, and 10 died before the IRA gave up. She has held tightly to a monetarist course despite unemployment of more than 3 million. Inflation is finally coming down; the latest treasury estimate for the year's end is 8 percent.

Opinion is divided over whether the Falklands will have any lasting impact on the economy, however. Columnist David Watt wrote in the London Times, "There is no particular reason to suppose that the qualities of patriotism and hardiness that proved so valuable in the Falklands effort are now transferable to less disruption or more managerial enterprise in British industry."

Chancellor of the Exchequer Geoffrey Howe believes they are, however. "Achievement in one area breeds confidence in another," he said after the Falklands victory.

Until now, the Labor Party and the new alliance of the centrists, the Social Democrats and Liberals, were counting on public disaffection with Thatcher's stubbornness in the face of widespread economic and social distress to help them. But for the moment, at least, the Falklands factor apparently has made the Thatcher determination an asset. Moreover, Labor and the Social Democratic-Liberal alliance are divided over internal tactics and policy objectives, and this division gives the conservatives a further advantage. Labor leader Michael Foot was widely considered ineffectual in rallying his party during the war crisis. The alliance standing has dropped as precipitously in the polls as it rose only a few months ago.

Thatcher has resisted suggestions that she call a national election to secure her mandate. Her political advisers say that she will wait, as she had always planned to, until October 1983, about six months before her five-year term expires.

"Whatever happens between now and then," one of her advisers said confidently, "one part of the Tory appeal to the voters is going to be, 'Look at who'll be in charge--Margaret Thatcher or Michael Foot,' and there won't be any question about the outcome."

Predictably, opposition spokesmen are less certain that the Falklands aftermath and Thatcher's positions generally will transform the British political landscape. "The danger of instant popularity," said Richard Clements, a senior aide to Foot, "is that it can disappear as fast has it appeared." He and others believe that the Falklands euphoria will subside quickly, leaving the high costs of maintaining the garrison there as the only legacy while the same economic problems Britain has been grappling with for years will remain and even worsen.

The selection Friday of Roy Jenkins to lead the Social Democrats and the Social Democratic-Liberal alliance in the next election means that Thatcher will need to appeal to moderates in her own party who might be drawn to the centrists if her rigid and ideological approach does not seem to be working.

Jenkins has promised to wage the election battle on economic issues, which he said have greater lasting significance for the country than a military campaign that will quickly recede from public consciousness.