Canada was plunged into a February general election last night when the minority Conservative Government lost the confidence of the House of Commons.

After losing the confidence vote on the issue of his Government's first budget, Prime Minister Joe Clark told the Commons he would ask Governor-General Edward Schreyer today for a dissolution and an election, probably on Feb. 18.

The defeat casts doubt on the measures announced in Tuesday's budget, because now there will be no Parliament to enact them. A spokesman for the Department of Finance said last night there is no legal provision for the collection of any of taxes that had been changed in the budget. An aide in Finance Minister John Crosbie's office added that the Government was studying the situation and would have a further statement today.

Mortgage scheme is dead Oil companies have been collecting the 5.5-cents-a-litre excise tax on gasoline in anticipation of the passage of the budget, but the Government has not yet received any of the money from them. It is expected there will be public pressure for the companies to lower their prices by eight cents a litre for a couple of days as a way of returning the excess revenue to consumers.

As for the Tories' mortgage-interest-deductibility scheme, it is definitely dead, despite its inclusion in income tax forms already being mailed to the public.

When the results of the 139-133 vote were announced, MPs and the packed Commons galleries burst into applause as a day of intensifying drama reached its climax. A combination of ll2 Liberal votes and 27 NDP votes defeated the Government, which had three members absent and was denied the support it had received in three previous confidence votes from the Social Credit caucus.

This time around the five Creditistes said they could not stomach the 18-cent-a-gallon increase in the gasoline excise tax, so they either stayed away or abstained last night.

Liberals ponder leadership Besides the status of the budget provisions, the most obvious immediate question arising from the Government's defeat is who will lead the Liberals in the campaign. Liberal Leader Pierre Trudeau has already announced his intention to resign, and the party has called a leadership convention for March 28-30.

The Liberal caucus meets this morning to discuss the leadership question, and many Liberal MPs said last night they expected the caucus unanimously to ask Mr. Trudeau to lead them in the campaign. There were also reports that the party has booked the Civic Centre in Ottawa for mid-January.

As soon as the Government fell, Tories, Liberals and New Democrats rushed to blame each other for precipitating an election.

The Liberals and NDP charged that the Tories had introduced a budget so onerous for ordinary Canadians that the Government actually invited an election. But Prime Minister Clark blamed the Opposition parties for provoking a confrontation.

'Not our choice,' Clark says ''The opposition parties have decided to disrupt the nation's business. That was not our choice; we wanted to get on with governing the country, Mr. Clark said. ''But the decision has been made by the Liberals and the NDP. I, of course, accept it. . . . ''Only six months ago, Canadians voted to change the Government of Canada because they wanted to change the direction of the country. By their action tonight, the opposition parties are saying Canadians were wrong in that decision.

NDP Leader Edward Broadbent, whose party's motion condemning the Government's budget and record of broken promises formed the basis for the defeat, said Mr. Clark himself was to blame for the election. ''Instead of listening and carrying out his own mandate, he did just the opposite, Mr. Broadbent said, alluding to the Conservatives' broken campaign promises.

Ever since the budget was introduced on Tuesday night, the Liberals vowed to bring down the Government. In the face of many who doubted their resolve, the party leadership got all but one Liberal MP - Serge Joyal (Hochelaga-Maisonneuve) - out for the vote. Two Liberal MPs released from hospital yesterday arrived in time for the vote. As they entered the Commons, both Maurice Dionne (Northumberland-Miramichi) and Claude Lajoie (Trois Rivieres) were greeted by thunderous applause from the Liberal benches.

On the Tory side, External Affairs Minister Flora MacDonald was in Europe on official visits; Lloyd Crouse (South Shore) was on vacation in Australia and Alvin Hamilton (Qu'Appelle-Moose Mountain) was ill.

Even if the three missing Tories had been present, the Government would still have fallen. In fact, the Government's life was effectively put to an end earlier in the day when the Social Credit caucus decided to abstain.

Only two Social Credit MPs were in their seats during the vote, and both remained seated throughout. Two others, including party leader Fabien Roy, refused to enter the Commons. The party's other member, C. A. Gauthier (Roberval), stayed in his constituency.

Last night's defeat represented only the fourth time in this century that the Government has been defeated on a non-confidence vote, thus bringing on an election.

In 1974, Mr. Trudeau's minority Government engineered its own defeat and then went on to win a majority. Conservative Prime Minister John Diefenbaker lost the confidence of the House in 1963 as did Prime Minister Arthur Meighen in 1926.

Mr. Clark did not announce a date for the election last night, but he is thought to favor Feb. 18, although the Chief Electoral Officer would prefer Feb. 25. The Prime Minister will reveal the date today after seeking a dissolution. Governor-General Schreyer has the prerogative of refusing the dissolution and calling on Mr. Trudeau to try to form a government, but this option was discounted by spokesmen for every party last night.

Of the 31 previous federal elections, there has been only one other in February. That came in 1887, and there have been only four elections from December to March since then.

Although no one likes campaigning in the dead of the Canadian winter, all three major parties thought they could improve their positions in the election.

The Conservatives could have tried to strike some sort of deal with Social Credit for their continued support. But the Social Credit demand for elimination or reduction of the gasoline excise tax - the heart of the Government's budget - precluded any negotiations. The Conservatives did not even try to make contact with the Social Credit yesterday, although rumors about a possible deal (and rumors on just about everything else) swirled through Parliament yesterday.

The Conservatives are confident the tough budget they have introduced will be accepted by the Canadian people as necessary medicine for an economy left in disarray by the Liberals. ''They're looking disgruntled because they think they are the natural rulers of Canada and, Christ, I'm dying to get at them, Mr. Crosbie said in reference to the Liberals.

The Liberals, however, think the Government's record is so poor and the budget so unpopular that they will sweep back into power, even though the party's leadership question is not resolved.

The NDP, buoyed like the Liberals from a recent Gallup Poll showing major gains for both opposition parties, believes the electorate will put a plague on both the Liberal and Conservative houses.

The Commons voted on an NDP motion which read: ''And this House unreservedly condemns the Government for its outright betrayal of its election promises to lower interest rates, cut taxes and to stimulate the growth of the Canadian economy, without a mandate from the Canadian people for such a reversal.

Interact with The Globe