The controversial former prime minister this morning used a major speech in central London to launch his bid to create a “movement” campaigning to reverse the Brexit vote on June 23 last year.
Mr Blair described it as his “mission” to persuade the British people they had made the wrong decision at the EU referendum and had “voted without knowledge of the true terms of Brexit”.
Insisting he is not calling for a new political party to fight against leaving the EU, Mr Blair demanded a cross-party campaign to tackle the Government’s Brexit strategy.
The ex-Labour premier told an audience at Bloomberg: “What was unfortunately only dim in our sight before the referendum is now in plain sight.
“The road we're going down is not simply ‘hard Brexit’. It is Brexit at any cost.
“Our challenge is to expose relentlessly what this cost is, to show how the decision was based on imperfect knowledge which will now become informed knowledge.
“To calculate in ‘easy to understand’ ways how proceeding will cause real damage to our country; and to build support for finding a way out from the present rush over the cliff’s edge.
“I don't know if we can succeed. But I do know we will suffer a rancorous verdict from future generations if we do not try.”
Asked how he planned to reverse the Brexit decision, Mr Blair insisted there would be “different ways” to overturn the June 23 result.
He said: “The issue of how a change might manifest itself is in my view a second-order question. What I think we need to do is very, very simple.
“We need to build sufficient understanding amongst the British people and a sufficient sense that 'no, having look at what's being offered, this is not such a good idea'.”
Quizzed again on whether he backed a second vote on Brexit, Mr Blair replied: “You could have a second referendum, you could do it in different ways.”
But the former Labour leader insisted a second EU referendum was “not the issue” and claimed there was “no point” in having another vote unless “it’s clear” there had been a change in public opinion.
Mr Blair said: “There are lots of way you can test opinion. There will be polls, there will be MPs coming back from their constituencies saying 'you know what, the mood has changed'.
“This is what's important, to create a different mood about this. then you can decide whether it's worth people having a second choice.”
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Tony Blair told Brexit supporters they 'voted without knowledge'
Attacking current Labour leader Jeremy Corbyn, Mr Blair asked: “Right now where's the pressure on the Government? The pressures all one way.”
He added: “The will of the people is not some fixed, immutable thing that can never change irrespective of the facts that are brought to their attention.”
In his speech Mr Blair, who chose not to place immediate transitional restrictions on immigration from new EU member states during his years in Downing Street, suggested migrants coming from the bloc were not the prime factor in the Brexit decision.
He said: "It is highly unlikely that they're ‘taking’ the jobs of British born people."
Instead, Mr Blair claimed voters were most concerned about immigration from outside the EU.
He said: "For many people, the core immigration question – and one which I fully accept is a substantial issue – is immigration from non-European countries, especially when from different cultures in which assimilation and potential security threats can be an issue.
“Yet this impacted the Brexit decision."
Mr Blair referenced Nigel Farage's controversial Brexit campaign poster of Syrian refugees travelling across Europe and Donald Trump's claim the UK wouldn't have voted to leave the EU without the migrant crisis across the continent.
Patronising speech from Tony Blair. Makes me more determined to ensure decision of the British people to Leave is fulfilled @labourleave
— Kate Hoey (@KateHoeyMP) February 17, 2017
Mr Blair admitted "of course" Britain "can and would survive out of the EU", adding: "This is a great country, with resilient and creative people.
"And yes, no one is going to write us off, nor should they. But making the best of a bad job doesn't alter the fact that it isn't smart to put yourself in that position unless you have to."
But he warned the UK might not survive the Brexit vote.
Mr Blair said: "The possibility of the break-up of the UK – narrowly avoided by the result of the Scottish referendum – is now back on the table, but this time with a context much more credible for the independence case.
“We are already seeing the de-stabilising impact of negotiation over border arrangements on the Northern Ireland peace process."
In a thinly-veiled attack on current Labour leader Jeremy Corbyn, Mr Blair claimed Labour's weakness as an opposition meant the party is now the "facilitator of Brexit".
He called for pro-Remain supporters to "build a movement which stretches across party lines" and to "find ways of concerting strategy and tactics effectively" in the fight against Brexit.
Mr Blair said: "We need to strengthen the hand of the MPs who are with us and let those against know they have serious opposition to Brexit at any cost."
I agreed with every single word of that.
— Nick Clegg (@nick_clegg) February 17, 2017
This is not the time for retreat… but time to rise up.
Having recently closed his business interests, Mr Blair declared his new institute would provide a "policy platform" for anti-Brexit campaigners.
He highlighted an "incontrovertible characteristic" of today's politics as the "propensity for revolt" by voters.
Mr Blair said: "The Brexiteers were the beneficiaries of this wave; now they want to freeze it to a day in June 2016.
“They will say the will of the people can't alter. It can.
“They will say Leaving is inevitable. It isn't.
“They will say we don't represent the people. We do, many millions of them and with determination many millions more.
In a message to pro-EU supporters, Mr Blair said: "This is not the time for retreat, indifference or despair; but the time to rise up in defence of what we believe – calmly, patiently, winning the argument by the force of argument,
"But without fear and with the conviction we act in the true interests of Britain."
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
Responding to Mr Blair’s speech, Vote Leave campaigner and Tory MP Michael Gove said: "People want politicians to get on with the job of making a success of leaving the EU rather than fighting old political battles.
"Tony Blair had his say during the referendum – he should now respect the fact that the British people voted to leave.
"Politicians like Tony Blair should respect the result and work with the Government to make a success of Brexit instead of trying to undermine British democracy."
Fellow Tory MP and Brexit supporter Dominic Raab, a member of the Exiting the EU Select Committee, said: “However they voted in the referendum, most people have accepted the result and now want the UK to get on with making a success of its new place outside the EU.
“Tony Blair, who allowed uncontrolled migration from the EU when Labour was in power, refuses to accept the decision people made last June.
“He wants to go on putting the question over and over again until he gets a different answer.
"It is the height of arrogance and nothing could be more likely to convince the EU to offer the UK the worst possible deal than his suggestion that the decision could be overturned.”