The former attorney general and Tory MP has questioned what the Conservative party is trying to achieve through its plan to replace the Human Rights Act with a British "Bill of Rights".
The proposal has left many lawyers aghast and Dominic Grieve, who was a barrister before entering politics warned the consequences for Britain's reputation in the wider world would be "very considerable" if it were to abolish the act.
He also insisted there is no "quick fix" because the act is "well embedded" in the constitutional settlements that underpin devolution, making it difficult to do anything against the wishes of the Scottish, Welsh and Northern Irish governments.
He told Sky News: "Is it merely a cosmetic change or is it a desire to do something radically different?"
"The latter would pose problems in relation to Britain's relationship with the Council of Europe, he said, as well as the European Union, which requires its member states to adhere to the convention.
Other than that, he insisted, the question was "totally unconnected" to the EU referendum, calling the discussion of the Bill of Rights - promised in the Conservative manifesto - "a bit of a distraction".
He also stressed the Supreme Court is "already supreme" and suggested the government was promising something that already exists.
While he said he understands the need to clarify the situation, he added: "It's not at all clear as to what we are trying to achieve.
"At the end of the day, what are the benefits going to be compared to the costs of change?"
He also pointed out that leaving the European Convention on Human Rights would not make it easier to remove people from the UK because the problems in doing so are often down to other countries refusing to take them or denying they are the nation of origin.
He said it is often the international Convention against Torture which prevents individuals being returned.
Former shadow home secretary and fellow Tory David Davis has hinted he might rebel in any vote on abolishing the Human Rights Act.
He told The Hull Daily Mail: "I'm afraid we will come into conflict with the European court and I don't want us to leave it.
"If we leave, it's an excuse for everyone else to leave. So I think that could be quite an interesting argument, come the day.
"I think it is more likely there will be an argument over that than over Europe."
Lord Falconer, the new Shadow Lord Chancellor and Shadow Secretary of State for Justice, said: “The Conservatives and their new Secretary of State for Justice appear all over the place on human rights.
“The UK Government should not be sending the message that it is undecided on whether it continues to support human rights and their incorporation into UK domestic law.
"Labour unequivocally supports Human Rights and their incorporation into UK domestic law. We will resist any attempts to dilute the commitment to human rights.”