And he will also warn that any concession to demands from hard-line Remainers to dilute the break from the EU would be “a disastrous mistake”.
His remarks today, in the first of a series of high-profile speeches from senior Cabinet ministers designed to flesh out the Government’s Brexit plans, is designed to inject some passion and optimism into the debate around Britain’s departure from the EU.
It will also been seen as a warning to Theresa May not to give in to pro-Brussels Cabinet ministers attempting to halt a clean break with the EU.
Some Tories fear Mr Johnson could quit the Government if the Prime Minister fails to face down pro-Brussels Tories including Chancellor Philip Hammond demanding continuing close ties to Brussels.
Mr Johnson will today hail Brexit as a cause for “hope not fear” in a passionate rallying cry
In his speech in Westminster today, the Foreign Secretary will say that leaving the EU is “not grounds for fear, but hope”.
Mr Johnson, who was one of the most high-profile backers of the Leave campaign in the run up to the 2016 EU referendum, is to say the time has come for politics to move on from the divisions of the past.
He will also set out his ideas for reuniting the country – and the bitterly divided Tory party – by insisting that Britain can succeed as a “great global power” and an independent nation.
Some Tories are certain to see his speech today as his blueprint for an alternative Brexit vision should the Prime Minister be forced out of Downing Street.
Mr Johnson will also set out his ideas for reuniting the country
The Foreign Secretary is expected to say: “I fear that some people are becoming ever more determined to stop Brexit, to reverse the referendum vote of June 23 2016, and to frustrate the will of the people.
“I believe that would be a disastrous mistake that would lead to permanent and ineradicable feelings of betrayal.
“We cannot and will not let it happen.
“But if we are to carry this project through to national success – as we must – then we must also reach out to those who still have anxieties.
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“I want to try today to anatomise at least some of those fears and to show to the best of my ability that they are unfounded, and that the very opposite is usually true: that Brexit is not grounds for fear but hope.”
Mr Johnson is expected to argue that Britain must not “repeat the mistakes of the past” when the pro-Brussels establishment ignored the concerns of much of the country.
“It is not good enough to say to Remainers – you lost, get over it; because we must accept that many are actuated by entirely noble sentiments, a real sense of solidarity with our European neighbours and a desire for the UK to succeed.”
Mr Johnson’s long awaited speech comes ahead of a crunch meeting of Mrs May and Angela Merkel at the end of this week.
The Prime Minister is due to hold talks with the German Chancellor on Friday in an attempt to kick-start the stalled Brexit talks.
Mrs May will then make a major speech on security to a summit on Munich on Saturday. She is expected to make an ambitious offer that Britain will continue to support European security after the country quits the EU.
The speeches by the Prime Minister and Foreign Secretary mark a new Government charm offensive ahead of the next round of Brexit talks.
The Prime Minister is due to hold talks with the German Chancellor on Friday
It comes as Chancellor Philip Hammond tours European capital this week in a new push to build support for a UK-EU trade deal.
Mr Hammond said yesterday: “I am taking the message to Europe that, while we are leaving the EU, Britain still cares about its relationships with the countries, citizens and businesses with whom we share a close history and common values.
“We look forward to agreeing a new, deep and special partnership with the EU that keeps our relationship growing strongly in the future.”