Top Tory MP Tobias Ellwood today announced he will be submitting a letter of no confidence in Boris Johnson.
The former minister and current Defence Committee chairman is one of the most senior Tories yet to demand the Prime Minister quit.
It ramps up the danger of 54 MPs submitting letters to trigger a no confidence vote, after David Davis and Andrew Mitchell also publicly said the PM should go. Mr Davis later confirmed he had not actually submitted a letter.