The Foreign Secretary will say concerns about Brexit are based on “noble sentiments” in an address that will present the government’s vision of an outward-facing, liberal UK.
Mr Johnson’s speech will be the first in a series of six major public statements over the next fortnight, including two by the Prime Minister, in a bid to seize back the initiative on Brexit and show the government is united behind a plan for a future outside the EU.
“It is not good enough to say to Remainers – you lost, get over it,” Mr Johnson will say today in London. “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.”
The Foreign Secretary, who was the leading campaigner for Leave in 2016, will seek to unite the country behind the goal of making Brexit a success, warning that any attempt to block the UK’s exit from the EU would spawn “ineradicable feelings of betrayal”.
Mr Johnson is expected to say: “I fear that some people are becoming ever more determined to stop Brexit, to reverse the referendum vote of 23 June 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.
“I want to try today to anatomise at least some of those fears and to show that they are unfounded, and that the opposite is usually true: that Brexit is not grounds for fear but hope.”
Brussels has put pressure on the government in recent weeks to spell out its plans for the UK’s future relationship with the EU, with the two sides yet to seal agreement on a post-Brexit transition phase.
Theresa May will hold talks with German Chancellor Angela Merkel in Berlin on Friday, with Chancellor Philip Hammond already embarked on a Brexit charm offensive that will take him to Norway, Sweden, the Netherlands, Spain and Portugal this week.
Mrs May will give a speech in Munich on Saturday dealing with future security co-operation with the EU.
It comes as MPs warned that the UK Border Force is ill-equipped to cope with any additional checks on EU nationals arriving in the UK after Brexit.
In a report published today, the Commons home affairs committee raised concerns over the impact of a major increase in activity for the agency, claiming it is already stretched due to “inadequate resources”.
Ministers have been urged to set out whether they want additional border checks on Europeans after Britain’s departure in March 2019.
Labour MP Yvette Cooper, who chairs the committee, said: “The government does not seem to appreciate the immense bureaucratic challenge they are facing or how much time and resources they need to plan on Brexit.
“The Home Office will end up in a real mess next year if there isn’t enough time to sort things out.”