“I’m in this for the long term,” she declared, spelling out a mission to give Britain a “brighter future … Standing tall” on the global stage.
Her shock defiance will have a potentially incendiary effect in a party still battered by June’s botched election campaign that cost the Tories their majority.
It is also at odds with her own contrite promise to dismayed Tory MPs just after the election that she would stay only as long as they wanted her to dig the party out of the “mess” she had plunged it into.
Her insistence that she has a long term vision for Britain and means to see it through is a gamble designed to strengthen her hand against plotters.
But many will think it an in realistic promise which could easily backfire and her enemies will recall the massive U-turn she performed on her previous vow not to call an election before 2020.
The widespread assumption of many was that she would stay to deliver Brexit in 2019 then make way for a successor to take the country forward.
Some MPs want her to go much earlier.
But she firmly denied speculation including one report she had hatched a plan – designed to keep her unhappy MPs in check during Brexit talks – to quit at the end of August 2019.
That would be five months after Britain is likely to have left the European Union and three years ahead of the latest date for the next election, in 2022.
Her determination to stay the course was revealed as she arrived in Japan for three days of talks about security and post-Brexit trade.
Asked by reporters travelling with her If she intended to fight the next election she said: “Yes, there’s been an awful lot of speculation about my future which has no basis in it whatsoever.
“I’m in this for the long term.
“There’s a real job to be done in the United Kingdom.”
Pressed to confirm she would not quit before the next election she responded firmly: “I’m not a quitter.”
Pressed explicilty to say she intended to lead her party into the next election, she said: “Yes. I’m here for the long term and it’s crucial, what me and my government are about is not just delivering on Brexit we are delivering a brighter future for the United Kingdom.
“We need to get the Brexit deal right, deliver the right deal for the people of the UK but we also need to ensure that after we have left the European Union, global Britain is out there trading around the world, standing tall in the world and that we deal with some of the remaining injustices at home.”