Robert Jenrick warned Tory MPs that they would have to sign up to Britain pulling out of the European Convention on Human Rights to stand at the next election if he becomes party leader.
He stressed it would be a manifesto commitment which they would have to support.
Asked on the BBC radio’s Westminister Hour, if MPs who voted against leaving the ECHR would lose the party whip, Mr Jenrick said: “Well, there won’t be a vote on that whilst we are in opposition.
“But if we were lucky enough to win the next general election, then this would be part of our manifesto.
“So yes, it would be Conservative Party policy, and those choosing to stand at the election would have to support it, as they do any other important policy that’s part of the manifesto...”
He added: “I’ve been very clear this would be a manifesto commitment of our party and it is a recipe, frankly, for more disunity and further loss of public trust just to kick these issues into the long grass.
“And anyone who chooses to stand as a Conservative would have to sign up to it, as they do anything else that’s in a manifesto.”
The hardline stance by Mr Jenrick, who argues that leaving the ECHR is necessary for the Government to gain control of immigration to the UK, has echoes of the deeply controversial approach taken by Boris Johnson over Brexit.
As Prime Minister, he expelled 21 MPs from the parliamentary Conservative Party in September 2019, after they revolted against him in a bid to prevent a no-deal Brexit.
They include two former Chancellors, Ken Clarke and Philip Hammond who are both now in the Lords, several other former Cabinet ministers including David Gauke, Justine Greening, and Greg Clark, and Winston Churchill’s grandson Sir Nicholas Soames.
Mr Jenrick and ex-Business Secretary Kemi Badenoch, who are both on the Right of the Tories, are seeking to win over party members after making it to the shortlist of two candidates for the run-off in the leadership contest.
Ms Badenoch is not advocating quitting the ECHR, warning it could have repercussions as Brexit did such as over trade for Northern Ireland, and suggesting it is a distraction from bigger concerns and not a properly thought-out move.
“We need to stop blaming the EU or international agreements and start fixing problems here ourselves,” she says.
Former Foreign Secretary James Cleverly was knocked out of the race in a shock result in the final vote of MPs, amid claims that some of his supporters had backed Mr Jenrick or Ms Badenoch, to try to engineer their preferred choice of the two contenders to make the shortlist.
Mr Cleverly’s allies have denied any co-ordinated move to achieve this aim.
The result of the vote by party members will be announced on November 2.
