In written evidence to the Scottish Parliament’s European and External Relations Committee on Brexit implications for Scots law, the Faculty said it was difficult to offer more than general thoughts when there was almost no clarity on when or how Brexit was to be realised.

But it was clear that withdrawal from the EU would remove a source of law which had been present for more than 40 years.

“It appears to us to be inconceivable that it will be possible to review all that law, and determine what to keep and what to remove, in time for the last day of the UK’s membership of the EU,” said Gordon Jackson QC, Dean of Faculty.

“Some kind of transitional legislation, providing that European law in force at the date of Brexit remains in force until repealed or replaced, appears inevitable.”

The Faculty noted the “many instances” of domestic law having been made to implement obligations under a European directive.

“Once Brexit has taken place, the extent to which courts should make reference to such directives and, especially, continuing case law of the European Court of Justice, as an aid to interpretation, will be less certain, especially as one moves further in time from the passing of the implementing legislation,” added Mr Jackson.

“On any view, the status of the decisions of the CJEU will become only persuasive rather than binding.

“There are also areas where the domestic law represents the UK’s implementation of European directives but does not now specifically refer to those directives…There is no reason why, following Brexit, such legislation should not remain in force unless and until the relevant parliament considers that it should be repealed or amended.”

The Faculty also pointed out that, after Brexit, the possibility of a reference from a UK court to the CJEU for an authoritative ruling would disappear. Authoritative interpretation would then be for domestic courts and, ultimately, for the Supreme Court.

And in areas which have been strongly influenced by the EU, such as equal opportunities and consumer rights, but which are reserved under the devolution arrangements, the legislative supremacy of Westminster is likely to assume greater importance to determining the content of Scots law.