Blair wants Labour to oppose any general election move by Tories until Brexit is resolved
Tony Blair will call for Labour to oppose any move by Boris Johnson to hold an emergency general election until Brexit has been resolved.
The former prime minister will say Labour should not "fall into the elephant trap" of backing a Westminster poll if MPs cannot agree on Brexit.
Mr Blair will add that Labour should throw its weight behind supporting legislation to prevent a no-deal Brexit, not a vote of no-confidence in the government.
In an address at the Institute for Government today, Mr Blair will say: "Should the government seek an election, it should be refused in favour of a referendum.
"It is counter-intuitive for opposition parties to refuse an election. But in this exceptional case, it is vital they do so as a matter of principle, until Brexit is resolved.
"Brexit is an issue which stands on its own, was originally decided on its own and should be reconsidered on its own.
"But the Brexiteers are laying a trap, to seem as if pushed into an election against their will, when they're actively preparing for it."
Mr Blair will praise Labour leader Jeremy Corbyn for his stance.
He will say: "In backing away from the idea of himself as a 'caretaker prime minister' Jeremy Corbyn has behaved responsibly, and if he continues to put the country first, he will benefit the country and himself.
"He can now play a decisive role in how Brexit develops.
"But he should see an election for the elephant trap it is.
"If the government tries to force an election, Labour should vote against it."
Warning against the consequences of leaving the EU without an agreement, Mr Blair will say: "We are poised to leave Europe on October 31 with no-deal and no idea frankly of what it really means.
"It could be difficult, damaging, or disastrous. This is a reckless path. But there is a strategy behind it, and we must be equally strategic in opposing it.
"First, the June 2016 referendum cannot be taken as a mandate for a no-deal Brexit.
"Feeble attempts to suggest it is have foundered on the overwhelming evidence that, on the contrary, Brexiteers continually stated that there would be a deal and that it would be easy.
"Second, therefore, if the government policy is to come out with no-deal, then either Parliament should agree it, or the people.
"Third, and this is the crux, if Parliament cannot agree, then the right way to consult the people is not through a general election but through a referendum."
Meanwhile, Jeremy Corbyn will insist Labour is doing everything necessary to "bring Britain back from the brink" of Boris Johnson's Brexit plans. The Labour leader will use a speech in Salford today to claim the prospect of quitting the EU without an agreement next month is adding to the "damage" done by Tory rule.
Mr Corbyn will say that manufacturing workers have lost out on £55 a week since 2010.
Speaking ahead of a meeting of the shadow cabinet to discuss preventing a no-deal Brexit, Mr Corbyn will attack the Prime Minister's plans to suspend Parliament as an "attack on democracy which will be resisted".
Mr Corbyn is expected to say: "Today the shadow cabinet will be meeting to finalise our plans to stop the disaster of no-deal ahead of the return of Parliament tomorrow.
"Like all change, democracy was won from below, it wasn't handed down from above.
"So, when a prime minister who hasn't won an election and who doesn't have a majority decrees that Parliament will be shut down because he knows his plan for a disastrous no-deal doesn't have the votes, we say that is an attack on democracy which will be resisted."