OTTAWA - A critical vote that could bring down the minority Conservative government has been tentatively scheduled for next Friday, sources tell The Canadian Press.

The so-called ways and means motion is usually a routine matter that signals an impending vote on a budget bill, but this time might very well act as the trigger that launches an election.

Conservative sources say the motion is likely to be introduced on Sept. 18, and as per parliamentary rules must be voted on immediately. Prime Minister Stephen Harper will have just returned from a trip to the United States, and would be ready to visit the Governor General and kick off an election.

A spokesman for Government House Leader Jay Hill said meanwhile that "the final timing decision has not yet been definitely made."

All parties have braced themselves for an election that seems increasingly inevitable.

The Liberals have said they will no longer support the Conservatives, and the Bloc Quebecois seems ready to hit the campaign trail. That leaves the NDP to decide the fate of the 40th Parliament, and members there are sounding increasingly skeptical about the chances of a compromise.

"I really think that most people across the country are saying to themselves, can't these people talk and get something done on the important issues?" NDP leader Jack Layton said in an interview.

"I say to the Prime Minister again, that it's incumbent upon a prime minister in this country in a minority parliament to work with other parties."

Next week is shaping up as a full scale preview of an election campaign.

Layton will kick things off with a public speech to his caucus on Parliament Hill, outlining why his party is the only one truly interested in addressing the needs of Canadians.

Liberal Leader Michael Ignatieff will deliver a major speech to the Canadian Club the same day, outlining why his party would be the best positioned to manage the Canadian economy. A Liberal source said the speech will go into more detail on what the Liberal party would do, including their plan for slaying the deficit.

The Conservatives will continue to frame themselves as focused on doing the government's work, and will introduce a package of changes to Employment Insurance.

The Canadian Press has learned some of those changes will likely include measures that would stop the treatment of severance packages as earnings and an extension of benefits to those who have paid into the EI system for years.

Although the legislation won't be a confidence measure, it will be an important tool for the Tories. Voting against improvements that help the unemployed would put the opposition parties in a difficult position.

"It's going to be a circus on the other side," said one senior Conservative. "(Ignatieff) can't seem to take a position."