The former Attorney General has questioned what his own party is trying to achieve through its plan to replace the Human Rights Act with a new British Bill of Rights.
Dominic Grieve has urged a period of consultation ahead of a review before any changes are made by the Conservative government and warned that the consequences for Britain's reputation abroad would be "very considerable" if it were to abolish the Act.
The Tory MP 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' Murnaghan: "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?"