Sidewalks around London's Victoria Station are unlikely to be filled this summer, as they were last year, by hundreds of people queuing for four or five days to buy a ticket for the Laker Skytrain to New York.

This is not, as some might believe, because the sidewalks will be impassable with uncollected garbage or striking trade unionists. It's just that Laker's system of selling tickets has been changed to make long waits in line unnecessary.

Having weathered the first full year of lower transatlantic air fares with only a 4 percent increase in American visits to Britain, officials here are predicting that the number of visits this year will not considerably exceed the 1.85 million recorded in 1978. If there is a large increase in the world price of petroleum, the outlook is even more bearish.

Even if the recent spate of labor disputes continues into the summer, visitors are unlikely to be more than slightly discomforted. Most of the public services that have been disrupted have little direct impact on tourists.

Certainly, a mountain of garbage in Leicester Square shouldn't be enough in itself to deter a would-be visitor. Hotels have not been affected, nor so far have the airports or ground transportation, with the exception of the railways.

British Rail, whose trains were stopped by official strikes for four days in January, predicts that its labor troubles won't lap over into the tourist season. Like many disputes, those on the railways seem to be winter creatures. But if there are additional strikes, the Railways Board says it will "consider sympathetically" requests for partial refunds from holders of Britrail Passes who aren't able to use them on every day of their validity.

So far, officials say, there has been no indication that overseas publicity about strikes is causing cancellations. What cancellations there have been -- mostly from continental Europe -- are attributed to the severe weather this winter.

But tourist officials can glimpse a silver lining even before a cloud has formed. Ylva French, public relations officer of the London Tourist Board, said: "In a way, if the pound weakens that'll be another reason for coming to Britain."

The dollar has fared relatively well in Britain. Each pound (now worth $2) costs less than a dime more than it did last August. However, early indications are that London hotel prices will have risen by an average of 10-15 percent.

Tourist offices say that there should be room in all categories of accommodation throughout the summer, but they advise advance booking in any case. For travelers with less definite plans, the London Tourist Board runs an accommodation service from an office in Victoria Station.

The best bets for good, inexpensive eating remain Indian and Chinese restaurants. You're seldom more than a street away from one or the other. One of the better Indian restaurants in central London is also cheaper than most, perhaps because it's off the beaten track: the Khyber at 15 Seymour Place, W.I.

Among the special events of 1979 are the 900th anniversary of Winchester Cathedral and the 150th anniversary of the founding of the London Metropolitan Police. An exhibition about the "bobbies" will be mounted from May 8 to Sept. 30 at the Museum of London, itself well worth a visit in any year.

Tourist authorities continue to encourage visitors to venture outside London. They now estimate that 60 percent of overseas visitors' nights in Britain are spent outside the capital.

In addition to the May-October celebrations in Winchester, the city of Chester in northwest England is marking its 1,900 years of recorded history. During the spring and summer, there are several score local arts, music and literature festivals throughout the country. It is also the 200th anniversary of the construction of the world's first iron bridge, which still stands in Ironbridge Gorge in Shropshire. A museum complex there preserves artifacts of the Industrial Revolution.

A new museum of the Battle of Britain has been opened in the North London district of Hendon, adjacent to an existing Royal Air Force Museum.

For the brave and energetic, British Rail and a rented bicycle can be used in tandem to provide the best mobility in city and country. Bicycles are carried free on most trains, and in central London cycling is often the quickest and surest means of transportation. (No strikes on bikes.)