An Essex MP has written a letter saying Theresa May should be replaced as Prime Minister.
James Duddridge, MP for Rochford and Southend East, wrote to the chairman of the 1922 Committee calling for a change of leader.
"I write this with heavy heart; however, we now need a proper leadership election and to move on."
What is The 1922 Committee?
The 1922 Committee is made up of all the Conservative backbench MPs. That's MPs who are not in the cabinet or ministers.
Why is this letter important?
If the chairman of the 1922 Committee, Sir Graham Brady, receives 48 similar letters it would trigger a vote of no confidence in Teresa May.
MPs can retract their letters and only the chairman knows how many letters he holds at any one time.
Therefore, no one knows if their letter might be the one that could kick off a leadership contest.