Tory leadership hopeful James Cleverly has picked up further support as MPs voted in the latest stage of the race to replace Rishi Sunak.
The shadow home secretary was backed by Paul Holmes, who quit as a Tory whip in order to publicly support Mr Cleverly.
The result of the latest round of voting on Tuesday will see one of the remaining four candidates – Mr Cleverly, Tom Tugendhat, Kemi Badenoch and Robert Jenrick – eliminated from the contest.
A further vote by MPs on Wednesday will reduce the field to a final two, who will then go to a ballot of Tory members.
Mr Holmes used a Conservative Home article to announce he was resigning as a whip so he could waive the neutrality required by that position to endorse Mr Cleverly.
“I know that he is ready to act now, and ready to hit the ground running from day one,” Mr Holmes said.
“He is someone that can bring together a team from all wings of our party, a team that will focus relentlessly on delivery.”
Mr Cleverly, who was equal third with Mr Tugendhat in the last round of voting, became the bookmakers’ favourite after he urged party members to be “more normal” and “sell Conservatism with a smile” in a speech at the party’s conference last week.
Momentum for Mr Cleverly could leave Mr Tugendhat vulnerable when the result of the latest round of voting is announced at 3.30pm.
The four remaining contenders will be seeking to pick up the 16 votes that went to Mr Stride in the last round of voting, when the shadow work and pensions secretary was knocked out of the running.
Former minister and ex-MP Steve Baker, who is backing Mr Tugendhat, told the PA news agency that Mr Cleverly is “extremely affable” but said that “being affable is not in itself enough to be a successful prime minister”.
He said Mr Tugendhat was “better equipped to take the difficult decisions which need to be taken” and that his tone on issues like the European Convention on Human Rights is “far superior to Robert (Jenrick)”.
Former immigration minister Mr Jenrick has put leaving the ECHR at the centre of his campaign and sparked a backlash last week after he claimed in a video that UK special forces are “killing rather than capturing” terrorists.
Former business secretary Ms Badenoch faced criticism during the conference for having suggested statutory maternity pay places an “excessive” burden on small businesses.
She said in her conference speech that “I do not like to fight but I’m not afraid to fight”.
The new leader will be announced on November 2.
Mr Cleverly and Mr Jenrick have complained that the drawn-out process will not conclude in time for a new Conservative leader to respond to Chancellor Rachel Reeves’ first Budget, which she will present on October 30.