Britain's Labor government suffered a stunning defeat tonight, losing a critical motion to curb debate on the bill to give Scotland and Wales limited home rule.

The vote against closure was 312 to 283. About 35 Labor members of Parliament defected, refusing to vote or joining the victorious opposition.

The setback probabaly kills the measure for this session of Parliament and severely crippls Labor in what has been its Scottish stronghold.

Although the authority of Prime Minister James Callaghan's government has been severely shaken, he has no present intention of resigning. But the defeat should embolden the Conservative opposition to intensify its pressure on the government. Moreover, the Tories will now most likely be joined by 11 Scottish Nationalists who will blame Labor for their frustration.

It is conceivable that this combination could wear the government down and force it to an early election. Given Britain's ailing economy, the Tories should win any general appeal to the voters in a walk.

For just this reason, Callaghan intends to hang on. Labor strategists figure that if they can stay in office another six months, North Sea oil should be flowing at a rate fast enough to wipe out Britain's deficit in its foreign accounts.

That would enable the government to revive the economy, cutting down on unemployment of about 5.5 per cent and lifting sagging incomes. Callaghan is hoping for a year of revival before he goes to the voters in late 1978 or 1979, precisely the strategy that the Tories hope tonight's vote will help upset.

The Scottish and Welsh nationlists regard the home rule bill as half a loaf at best, a way station on their real goal to reestablish independent, sovereign states.

Most Liberals did not like ti, arguing that it gives neither Wales nor Scotland enough real say in their own affairs. Only two of the 13 Liberals voted with the government tonight.

Most Tories and many in Labor oppose any weakening of Britain's central government by moving toward a federal structure. That is why about 35 of the 312 Labor parliamentarians took the remarkable step of defying their party's leadership.

The bill that was probably sunk tonight is a patchwork compromise at best. It would give an elected Scottish lwgislature considerable power to spend funds on domestic projects and serivces but would subject all is measures to a possible veto in London. Moveover, the local legislature would not have the authority to levy taxes, and essential power of any government. A proposed Welsh legislature would suffer even severer curbs.

Government strategists must now decide whether to make a fresh stab at conciliating opinion in Scotland, where a strong groundswell for either independence or home rule has developed. Callaghan might press for an advisory referendum on his bill as a device both to placate Scotland and put pressure on his party's defectors.