Nick Clegg has accused David Cameron of allying himself with Vladimir Putin and against human rights, as he launched a broadside against the prime minister's reshuffle.
The Lib Dem leader said the reshuffle exit of Attorney General Dominic Grieve and Ken Clarke, who had resisted calls to leave the European Convention on Human Rights, showed "the headbangers have now won" in the Tory party.
The prime minister has been presented with proposals on human rights law which would assert the sovereignty of Parliament, but the BBC reported that Grieve had warned against the changes before being sacked.
The report drawn up by a working group of Conservative lawyers predicts the plan for a British bill of rights could force changes in the way the European Court of Human Rights in Strasbourg operates.
But it also acknowledges the changes could lead to the UK being expelled from the 47-member Council of Europe which upholds human rights across the continent.
The BBC reported that Grieve had warned his colleagues the idea was a plan for "a legal car crash with a built-in time delay" and it was "incoherent" to attempt to remain a signatory to the European Convention on Human Rights without recognising the rulings of the court set up to enforce it.
Speaking on LBC Radio, Clegg said: "I have been completely blindsided today by hearing that the Conservatives, extraordinarily, want to line up with Vladimir Putin and other tyrants around the world by tearing up our long tradition of human rights."
He added: "It shows what the real significance of this week's Conservative Party reshuffle was. It's nothing to do with gender balance, it's all to do with the death knell of the reasonable internationalism of people like Ken Clarke.
"I think the headbangers have now won. They are now in effect saying that the Conservative Party wants to turn its back on a long, long British tradition of upholding human rights across the world.
"What on earth are we going to say to the dictators in Belarus, to Vladimir Putin, if we do what the Conservatives now appear to recommend, which is that we are going to stamp our little feet and not abide by binding international human rights practices and conventions - ones, by the way, which were drafted by British human rights lawyers in the aftermath of the Second World War?
"I think it's really sad to see a mainstream party like that turning its back on a great long-standing British tradition of standing up internationally for human rights.
"It's very revealing that that is apparently the most immediate knock-on effect of removing people like Dominic Grieve and Ken Clarke, is that you've now got a much more extreme view taking root in the heart of the Conservative Party."
The prime minister could set out the human rights proposals in his party conference speech later this year as he attempts to rally Tory support ahead of the general election.
Justice secretary Chris Grayling yesterday confirmed the Tories would set out their proposals for reform in time to be included in the party's manifesto.
Many Tories would like Britain to withdraw from the convention following a series of adverse decisions by the court in Strasbourg - including a ruling that prisoners should be entitled to vote.
Both Clarke and Grieve have warned strongly against any move to leave, arguing it would damage Britain's reputation and undermine the cause of human rights around the world.