With one year to go until Brexit, Theresa May is mounting a whirlwind tour of the four nations of the United Kingdom with a promise to keep the country "strong and united".
Speaking to voters in England, Scotland, Northern Ireland and Wales, Mrs May will say that, whether they voted Leave or Remain, what is important now is making Brexit "a success for everyone".
The PM's bid to heal divisions caused by the 2016 EU referendum comes as polls suggest voters are still split down the middle over whether or not the UK should leave.
As the final year countdown began, she was buoyed by the EU's approval for a 21-month transition period after the official date of Brexit on March 29 2019 to allow the UK to prepare for its new relationship with Europe.
But tough negotiations on the nature of the future relationship lie ahead over the months before a planned agreement in the autumn.
And the UK Government is facing stiff resistance from Edinburgh and Cardiff to plans to repatriate some powers from Brussels to London, rather than the devolved administrations.
Speaking ahead of her trip, Mrs May said: "I am determined that our future will be a bright one. It's a future in which we trade freely with friends and partners across Europe and beyond.
"Having regained control of our laws, our borders and our money, and seized the opportunities provided by Brexit, the UK will thrive as a strong and united country that works for everyone, no matter whether you voted Leave or Remain."
Mrs May insisted that each of the devolved administrations will see "an increase in their decision-making powers" as a result of the return of responsibilities currently exercised by the EU.
Her Government remains "absolutely committed" to the devolution settlements, she said.
And she restated her rejection of EU proposals which would effectively create an administrative border down the Irish Sea by keeping Northern Ireland in the Customs Union.
"As the Prime Minister of the United Kingdom, I have an absolute responsibility to protect the integrity of the United Kingdom as a whole," she said.
"That means ensuring that no new barriers are created within our common domestic market and that the UK is able to meet its international obligations in the future.
"No Prime Minister could leave these things to chance, because they are absolutely crucial to our success as a country in the future."
Mrs May said the Union delivered "enormous benefits" to all four nations of the UK.
And she declared: "I am determined that as we leave the EU, and in the years ahead, we will strengthen the bonds that unite us, because ours is the world's most successful union.
"The UK contains four proud and historic nations, but together we amount to so much more than the sum of our parts and our Union is an enormous force for good."
The PM will start the day by visiting textile workers at a factory in Ayrshire, before travelling to Newcastle to meet with a local parent and toddler group.
She will have lunch with farmers near Belfast before travelling to Barry in south Wales for a round-table discussion with businesses, and will later have tea in west London with a group of Polish citizens who have made the UK their home.