May reiterated that Britain would be leaving the European single market and the customs union and warned of tricky battles.
May reiterated that Britain would be leaving the European single market and the customs union and warned of tricky battles over the next two years as the country negotiates its departure from the European Union.
"Every vote for me and my team will strengthen my hand in the negotiations to come," May said at the launch in Halifax in northern England, calling it "a manifesto to see us through Brexit and beyond."
"If we fail, the consequences for Britain and for the economic security of ordinary working people will be dire. If we succeed, the opportunities ahead of us are great," May said, as dozens of anti-austerity campaigners and trade unionists rallied outside.
"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," May said.
May said leaving the EU meant making "tough choices".
"I have been clear that we do not seek to fudge this issue. We do not seek to be half-in, half-out," she said, referring to a "clear choice" made in last year's referendum in favour of Brexit.
"We will leave the European Union and take control of our money, take control of our borders, take control of our laws," she said to applause from the audience.
Halifax, which is currently held by the main opposition Labour Party, is a key target for Conservatives ahead of the June 8 election.
It voted strongly in favour of leaving the EU in last year's referendum -- in which a 52-percent majority in the country as a whole opted for Brexit.
But two polls published on Thursday showed Labour gaining some ground after the publication of their distinctly leftist manifesto earlier this week, although they are still trailing badly.
An Ipsos MORI poll put the Conservatives on 49 percent -- unchanged since April -- and Labour on 34 percent -- a jump of eight percentage points.
Ipsos MORI surveyed 1,053 adults by telephone between Monday and Wednesday.
The latest YouGov poll put the Conservatives on 45 percent -- down four points from May 11-12 -- and Labour on 32 percent, an increase of one point.
YouGov surveyed 1,861 adults on Tuesday and Wednesday.
The manifesto also includes promises to limit immigration from outside the European Union and to curb numbers arriving from within the EU.
"It is our objective to reduce immigration to sustainable levels, by which we mean annual net migration in the tens of thousands rather than the hundred of thousands we have seen over the last two decades," the Conservative manifesto said.
The promise to reduce net migration to the tens of thousands was also made and then broken several times by her Conservative predecessor David Cameron.
The Conservative manifesto also said welfare payments for older people would be cut to fund social care and free school provision would be reduced to boost investment in other parts of the education system.
Executive pay packages will be subject to annual votes by shareholders and listed companies will have to publish the ratio of executive pay to "broader UK workforce" pay in a concession to widespread public anger over high salaries for big business bosses.
The threshold beyond which people have to pay income tax will be increased to £12,500 a year from £11,500 and the 40-percent tax rate will apply to salaries of £50,000 and above instead of £45,000 now.
May said hers was a plan for "a stronger, fairer, more prosperous Britain".
The manifesto launch was held in Dean Clough Mills, a collection of 19th-century factory buildings that was once home to the world's largest carpet factory, and is now a sprawling arts and business centre.
Halifax was built on the cloth trade and is still relatively prosperous and has been Labour since 1987.
But the current MP, Holly Lynch, won the seat in 2015 with a majority of just 428 over the Conservatives.
The UK Independence Party came third with 12.8 percent of the vote in 2015, while Liberal Democrats trailed with 3.7 percent.