The Advocate General has launched an attack on the Law Society of Scotland over its position on Brexit, The Herald reports.

Leaked emails show that Richard Keen QC (pictured), a well-known Conservative, thought the Law Society’s briefing on leaving the EU was “political rather than legal”. Lord Keen of Elie is the chief legal adviser to the UK government on Scots law.

A member of staff in Lord Keen’s office emailed the Law Society’s president, Eilidh Wiseman and director of law reform, Michael Clancy, saying: “Thank you for your email of 30 January in relation to the European Union (Notification of Withdrawal) Bill. Lord Keen has asked me to convey that he has noted the terms of the communication but did not regard the comments as balanced.”

He continued: “He felt the references to the Miller case were selective and the views expressed appear to him to be political rather than legal.”

While the email did not specify a document, Mr Clancy had produced a briefing in which he outlined the society’s position.

It stated: “Whilst accepting that the UK Supreme Court has come to the view that the consent of the Scottish Parliament and the devolved Assemblies is not a legal requirement before the bill is passed it should also be noted that the Supreme Court judgment is not authority for interpreting the scope of the Sewel Convention.”

Mr Clancy continued: “It might be argued that a Bill which gives the Prime Minister a power, whose exercise will inevitably alter the competences of the Scottish Ministers and Parliament, will engage the convention. For example, the triggering of Article 50 will inevitably enlarge those competences by removing the constraints upon those competences of having to observe EU law (see para 132 of the Miller decision).”

Joanna Cherry QC MP, SNP justice spokesperson, said: “The Law Society of Scotland’s legal analysis of the Supreme Court’s decision in respect of the Sewel Convention is accurate and shared by other impartial legal experts such as Mark Elliott, professor of public law at the University of Cambridge.

“Lord Keen’s email is typical of the UK government’s hubris over Brexit and their desire to silence any meaningful debate or scrutiny and to rubbish intellectual criticism.”

A spokesperson for the Law Society said: “All of our work is apolitical and impartial. We will continue to engage with both the UK and Scottish governments over the coming months.”

A spokesperson for the Office of the Advocate General said: “The Supreme Court’s judgement was clear. We do not comment on leaked documents.”