The Prime Minister has claimed a change in leadership would put the UK's "future at risk" after a no-confidence vote was triggered.
Delivering a statement outside 10 Downing Street, Theresa May said a vote of no-confidence triggered by 48 MPs submitting letters against her, would create "uncertainty when we can least afford it".
"A leadership election risks handing control of Brexit negotiations to opposition MPs in Parliament," Ms May said.
- Read more: Vote of no-confidence in Theresa May triggered after 48 letters received
- Read more: Owen Paterson MP on no-confidence vote: 'All this monkeying around is making people angry'
"Weeks spent tearing ourselves apart will only create more division as we should be standing together to serve our country."
Ms May announced she had cancelled a planned trip to Dublin today in which she was set to meet with the Irish Prime Minister to "make the case" for her leadership with colleagues.
'Contest the vote with everything I've got'
She added: "I will contest the vote with everything I've got."
The no-confidence vote is expected to take place between 6pm this evening, with an outcome expected at 9pm.
A letter from the 1922 Committee confirming that enough Conservative MPs have requested a vote of confidence. Image: PA
If more than half of Conservative MPs vote against Theresa May, a leadership election will take place.
"I have devoted myself unsparingly to these tasks ever since I became Prime Minister, and I stand ready to finish the job," Ms May said.