Stephen Hammond, a Conservative MP, has revealed that he has written a letter of no confidence in Boris Johnson’s leadership.

Wimbledon MP says: “Since 9 December I have been critical of the prime minister’s behavior and the culture that existed in Number 10. All I can do as a backbencher is speak out and submit a letter. I guide everyone to my website statements where I have said for several months I already have done all I can as a backbencher.”

If the chairman of the 1922 committee of Conservative backbenchers receives 54 letters of no confidence, a vote will be held to determine if a leadership election should be held.

19 Tory MPs have officially called for Boris Johnson to resign, while 27 have expressed doubts about his future.

In the wake of the Sue Gray report, four Conservative MPs have called on Prime Minister David Cameron to resign.