John Scott's comments came ahead of an emergency Scottish cabinet meeting tomorrow to discuss the role of the UK Supreme Court in Scottish criminal cases, after it overturned a decision convicting Nat Fraser of murdering his estranged wife.
The summit, which will be attended by Lord Advocate Frank Mulholland, has been called to look at what options SNP ministers now have in the wake of the London-based court overruling the verdict of Scotland's High Court.
But Mr Scott, a solicitor advocate and chair of the Howard League for Penal Reform in Scotland, told The Scotsman that SNP ministers would not be able to get out of the influence that the Supreme Court has over Scotland's legal system, as only the UK government has the authority to alter the legislation.
He also dismissed First Minister Alex Salmond's claim that it was "totally unsatisfactory" for the Supreme Court to rule on Scottish cases, after judges ruled that Fraser's original trial at the High Court in Edinburgh for the murder of Arlene Fraser - who disappeared from her home in Moray - had been unfair.
The London-based court upheld the appeal of Fraser, who has been remanded in custody until 8 June pending a possible retrial, after his legal team argued there had been a miscarriage of justice.
Mr Scott warned ministers ahead of tomorrow's Cabinet meeting that ending the Supreme Court's role in Scotland's legal system would put the country out of step with the rest of the UK over human rights legislation.
He said: "The Scottish Government can't get out of it, as it would require the UK government to amend the Scotland Act and remove the Supreme Court's jurisdiction. If Alex Salmond and Kenny MacAskill decide they've had enough of it, we'd have a situation where the human rights legislation in Scotland was out of step with that of the rest of the UK.
"The Scottish Government seems to be saying we don't like the Supreme Court when it makes decisions we don't like."
However, a senior SNP MSP defended the Scottish Government's stance and called on ministers to hold a review of the Supreme Court's influence over the country's legal system.John Wilson said: "The Scottish Government is right because Scotland's legal affairs should be out with the jurisdiction of the UK's Supreme Court.
"I hope that the Cabinet agrees during tomorrow's meeting to hold a review of the role of the Supreme Court and how Scotland's judicial system deals with appeals similar to the Nat Fraser case."
A spokesman for justice secretary Kenny MacAskill said: "Tuesday's Cabinet meeting will be an opportunity for ministers and the country's top law officer to discuss possible remedies to a situation which has seen criminal cases taken outside Scotland for the first time ever, because the historic independence of Scots law must be defended.
"Scotland's distinct legal system, including our criminal law, has served our country well for centuries, ensuring justice for victims while also protecting the rights of those accused of a crime.
"We believe the UK Supreme Court should have no role in matters of Scots criminal law - a view supported by Scotland's leading legal figures, including the previous Lord Advocate."