The Scottish National party has accused the government of endangering the 300-year-old Acts of Union between England and Scotland by launching an inquiry into the role of judicial reviews that could lead to changes in Scottish law. Joanna Cherry QC, the party’s justice and home affairs spokesperson, has written to the justice secretary, Robert Buckland QC, pointing out that “Scotland’s system of civil justice is a devolved matter” and “therefore the preserve of the Scottish parliament”. Her intervention follows the announcement in July that the government has established “an independent review of administrative law” that will examine the role of judicial review challenges in the courts. Judicial reviews, through which the legality of government policies can be challenged in the courts, have proved highly effective in holding ministers to account – often providing more detailed scrutiny than parliament. Cases can be launched in any of the UK’s jurisdictions – England and Wales, Scotland or Northern Ireland – and be appealed all the way up to the supreme court, as happened in last year’s prorogation of parliament case, which resulted in a humiliating legal defeat for Boris Johnson. The investigation will examine whether judicial reviews should be codified, whether “certain executive decisions should be non-justiciable”, what grounds for challenge and remedies should be available, and whether the system needs reforming. The shadow justice secretary, David Lammy, criticised the initiative as an attempt to stifle dissent. “The judicial review process is how the public can use the courts to hold the government to account when it acts against the law,” he said in July. “This is a blatant attempt to disempower the public and hoard more power in No 10.” The Ministry of Justice confirmed that the review would cover all the UK’s separate jurisdictions. It is chaired by Lord Faulks, a former Conservative justice minister who is now sits in the upper house as an independent. Among other legal experts on the panel are Prof Alan Page, a constitutional specialist who is an adviser to the Scottish parliament. In his letter to Cherry, the justice secretary wrote that the review would examine “the balance of the interest of the citizen being able to challenge the lawfulness of executive action through the courts with the importance of the executive being able to govern effectively under the law”. In her reply, Cherry said: “The authority and privileges of the court of session including its inherent supervisory jurisdiction are protected by article 19 of the Acts of Union and the underlying treaty of union. The scope of the review also raises serious questions for the rule of law which will be of concern across the United Kingdom.” The Acts of Union were passed in 1706 and 1707 in both the Scottish and English parliaments. Jolyon Maugham QC, the founder of the Good Law Project who brought judicial review challenges in the prorogation case in the Scottish courts, supports Cherry’s concerns. He said: “Legislation to narrow the jurisdiction or powers of Scotland’s court of session would likely offend against article 19 of the Acts of Union which guarantees for all time “the same authority and privileges” as before the union. “It would be punchy of Westminster to rewrite that ancient constitutional settlement and undermine Scotland’s separate legal system at a moment when Brexit had already generated majority support for Scottish independence.” He suggested that if on the other hand the Scottish legal system was left unaltered and restrictive judicial review regulations introduced into England and Wales, it could result in some challenges moving from London to the Edinburgh courts. A Ministry of Justice spokesperson said: “Judicial review is an essential part of our democracy. The independent panel will ensure this important check on government power is maintained, while making sure the process is not open to abuse and delay. “The Scottish legal system has been distinct but entwined with the English and Welsh system for over 300 years and this panel has no intention of changing that. “Nonetheless, we have appointed an esteemed Scottish law academic to the panel to assess whether any changes might impact Scotland.”