Theresa May has promised that a Conservative government will tackle the "five giant challenges" facing Britain over the coming decade, as she launched the party's manifesto for the June 8 general election.
In a foreword to the document, being launched in the Tory target seat of Halifax in West Yorkshire, the Prime Minister warns that the next five years will be the most challenging period the UK has faced for 60 years.
As well as the massive task of pulling the UK out of the European Union, the government elected next month will need to deal with the challenges of building a strong economy, tackling social division, meeting the pressures of an ageing society and making sure that Britain responds to the upheavals caused by fast-changing technology, she said.
"The next five years are the most challenging that Britain has faced in my lifetime. Brexit will define us: our place in the world, our economic security and our future prosperity," said Mrs May.
"So now more than ever, Britain needs a strong and stable government to get the best Brexit deal for our country and its people.
"Now more than ever, Britain needs strong and stable leadership to make the most of the opportunities Brexit brings for hard-working families.
"Now more than ever, Britain needs a clear plan.
"This manifesto - Forward, Together: Our Plan for a Stronger Britain and a Prosperous Future - will meet the great challenges of our time, beyond Brexit.
"With this plan and with a strong hand through Brexit, we will build a stronger, fairer, more prosperous Britain for all of us."
Unveiling what she termed "my manifesto for Britain's future", Mrs May said it was: "A manifesto to see us through Brexit and beyond, a plan for a stronger, fairer, more prosperous Britain, a plan to seize the opportunities ahead and to build a country that our children and grandchildren are proud to call home."
She said the document set out "a vision for Britain, a portrait of the kind of country I want this nation to be after Brexit as we chart our own way in the world".
Mrs May warned that if the upcoming Brexit talks failed to deliver a good deal, "the consequences for Britain and for the economic security of ordinary working people will be dire".
But she said: "If we succeed, the opportunities ahead of us are great."
She promised that her government would be "relentless in tackling burning injustices" and would govern for "mainstream Britain".
"With the right Brexit, my mainstream government will deliver for mainstream Britain," she said.
Mrs May said as the UK left the EU, it would need to harness the talents of all its people.
"I believe we can and must take this opportunity to build a great meritocracy here in Britain," she said.
"It means making Britain a country where everyone of whatever background has the chance to go as far as their talent and their hard work will take them.
"It means making Britain a country that works not for the privileged few, but for everyone."
She warned that making a success of Brexit would not be easy.
"There will be obstacles in our way," she said. "There will be some who wish us to fall short, others who wish to hold us back, many others who will us to fail."
Repeating her pledge to help those who are "just about managing", Mrs May said: "For too many people in Britain today, life is simply much harder than many seem to think or realise.
"They just want to get on with their lives, to do their best for their children, and to be given a fair chance. And they look to their government for help and support. This party - the Conservative and Unionist Party - will be that government."
While government does not have all the answers, it "can and should be a force for good", she said.
In a clear swipe at Jeremy Corbyn's Labour Party, she said voters would not be fooled by "politicians who promise the Earth and claim no tough choices will be required".
She promised that the Conservatives would be "upfront and honest about the scale of the task we face".
Mrs May called on traditional supporters of all parties to rally behind her to ensure she has the strongest possible hand in Brexit negotiations.
"In this election - more than in any before - it is time to put the old, tribal politics behind us and to come together in the national interest: united in our desire to make a success of Brexit, united in our desire to get the right result for Britain," she said.
"Because every vote for me and my team in this election will strengthen my hand in the negotiations to come.
"Every vote for me and my team will be a vote to get on with the job of delivering Brexit and delivering a stronger, more secure future for all.
"Every vote for me and my team will be a vote for a stronger, fairer, more prosperous Britain.
"And after all that has passed, that is a vision of the future that can bring us together."
She urged voters: "Join me on this journey, come with me as I lead Britain, strengthen my hand as I fight for Britain, stand with me as I deliver for Britain.
"And with confidence in ourselves and a unity of purpose in our country, let us all go forward together."