In a provocative intervention coinciding with Ukip’s spring conference, the controversial ex-prime minister is expected to urge pro-Europeans to unite to fight a clean break "hard" Brexit.
He is also set to repeat his claim that Parliament and the public should have the last word – perhaps but not necessarily in a second referendum – on the Brexit deal which Theresa May strikes with the EU.
Tony Blair will make a high profile speech on Brexit today
Leave Means Leave co-chair Richard Tice said last night: "There is some irony that Tony Blair, a former prime minister who will forever be remembered for deceiving the British people, will try to resurrect his political corpse by trying to deceive the British people once again.
"The EU referendum was democratic, fair and free and the British people voted for Brexit.
"Tony Blair is now trying to do everything he can to halt Brexit.
The former Prime Minister is expected to be accused of trying to block Britain’s exit from the block
"Britain will thrive from the huge benefits Brexit brings by leaving the Single Market and Customs Union.
Tony Blair is now trying to do everything he can to halt Brexit
Leave Means Leave co-chair Richard Tice
"Out of touch, elitist, anti-democracy campaigners like Tony Blair should stop trying to sabotage this by damaging the strong negotiating position of Theresa May."
Mr Blair has ploughed more than £9million from winding up his complex web of companies into his new crusade against what the "new populism" he says is shown by events such as Britain's Brexit vote and the election of Donald Trump as US President.
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Mr Blair is also set to repeat claims that Parliament and the public should have the last word
The multimillionaire former Labour leader – a hate figure for many over taking Britain into the 2003 Iraq War and for his lucrative and controversial business activities since he left Downing Street in 2007 – has said he accepts people would not want him back in frontline politics big time.
But he believes his Tony Blair Institute can be a platform for debate among like-minded people.
Blair and Juncker: Together through the years
Wed, January 25, 2017
Former Prime Minister, Tony Blair and President of the European Commission, Jean-Claude Juncker have always shared a friendly relationship over the years.
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EU Commission President Juncker greets former British PM Blair in Brussels
The former Labour leader has plugged £9m into fighting what he calls ‘new populism’
Last year he claimed Brexit could be stopped because many Leave supporters would change their minds when they saw the economic case for it "didn't stack up".
He also urged the UK to keep its "options open" after the "catastrophe" of the referendum vote.
He told an interviewer in October that if it became clear Britain's Brexit deal made it not worth leaving, or too damaging, "there's got to be some way, either through Parliament, or an election, or possibly through another referendum, in which people express their view".