Tony Blair will enter the General Election fray today to warn a second term for David Cameron risks economic chaos and endangers the British national interest.
The former prime minister, speaking in his former constituency of Sedgefield, will warn Mr Cameron’s appeasement of right wing Tories and Ukip is pushing Britain toward Europe’s exit door.
Mr Blair’s appearance, alongside his wife Cherie, will be the first in a series of campaign stops over the coming days.
He will warn the possibility of a British exit from the European Union would create job insecurity and leave a “pall of unpredictability hanging over the British economy”.
Mr Blair will praise his Labour successor for showing “real leadership” in opposing an in-out referendum – though Ed Miliband will not be present, as he is due to be campaigning in the south west of England.
Mr Cameron is due to step up his own campaign with a national tour, starting in Scotland and taking in all four nations of the United Kingdom in a matter of hours.
In his speech, Mr Blair is expected to say: “I believe passionately that leaving Europe would leave Britain diminished in the world, do significant damage to our economy and, less obviously but just as important to our future, would go against the very qualities and ambitions that mark us out still as a great global nation.”
And he will add: “And the oddest thing of all about David Cameron’s position? The PM doesn’t really believe we should leave Europe; not even the Europe as it is today.
“This was a concession to party, a manoeuvre to access some of the Ukip vote, a sop to the rampant anti-Europe feeling of parts of the media.
“This issue, touching as it does the country’s future, is too important to be traded like this.”
Mr Blair will say he “respects” Mr Miliband’s decision to put the “interests of the country first”.
He will say: “He showed that on this, as on other issues, he is his own man, with his own convictions and determined to follow them even when they go against the tide.”
Mr Blair is expected to tell his audience those who want Britain to leave the EU have completely underestimated the challenges and implications of doing so.
He will urge voters to “reflect” on those seeking exit and ask whether they are “the standard bearers of an open-minded culturally tolerant Britain”, warning Ukip offers the “oldest politics in history”.
And he will set the issue in the strategic context of an aggressive Russia and the economic rise of China and India.
The three time election winner will say: “Do we really think this is the time in which to put into play our very membership of the European Union, the largest commercial market and most developed political union in the world? And the one on our doorstep?
“So that instead of playing a leading role in resolving these common challenges, we would decide to engage in the juddering impact of a negotiation which would weaken all these alliances and put us out of the leadership game?”
Mr Blair will add: “So think about that vote on May 7. Think of the consequences of a re-elected Tory Government making the central question of the next parliament whether we get out of Europe. Think about the risk. Think about our past and our future.
“I want Labour to win. I want us to win for the future of our country and its place in the world. I want Labour, under Ed’s leadership, to be the government of our country on May 8. I believe we can and will do it.”
The Prime Minister is to warn backing Mr Miliband would cause its own form of chaos.
Ahead of his whistlestop tour taking in Scotland, Northern Ireland, Wales and Cornwall, the Tory leader said: “Today, I am travelling to all four nations of our United Kingdom, to all four corners of our country, with one simple message: we have one month to save our economy from the disaster of an Ed Miliband government.
“We have one month to save Britain from his mountain of debt; one month to save Britain from his punitive taxes; one month to save Britain, and British families, from his anti-business and anti-aspiration agenda.”
He added: “The election isn’t just a choice between parties; it’s a choice between two different types of United Kingdom.
“One that lives within its means – or one that heaps more debt on our children.
“We’ve got just one month to make sure people choose the right path.”
Elsewhere on the campaign trail, Liberal Democrat leader Nick Clegg will visit north-west England and Mid Wales, while Ukip leader Nigel Farage will take a break from campaigning in Thanet to embark on regional visits in England.