The SNP has launched its own wildcat bill on Brexit following the failure of UK and Scottish governments to agree on the repatriation of EU powers.
The continuity bill was formally introduced on Tuesday in Holyrood as an alternative to the Conservative legislation, which the Scottish Government says is an attack on devolution.
Presiding officer Ken Macintosh ruled the proposed law is beyond the competence of the Scottish Parliament – but SNP ministers vowed to push it through if required.
Scotland’s Brexit Secretary Michael Russell said: “If the UK government drops its power grab then it may still be possible to reach agreement, in which case we would not need to proceed with the continuity bill.
“But we are proposing this bill should be put through on an emergency timetable to ensure it becomes law in time to make the necessary preparations.”
Both bills in Edinburgh and London transfer EU laws in force in the UK onto domestic statute books on the day Britain stops being part of the bloc to ensure there are no gaps in legislation.
Nicola Sturgeon says the UK version of the bill is a “power grab” because some devolved powers currently controlled by Brussels, including those on agriculture and fisheries, will revert back to Westminster.
The UK Government’s position is that the London parliament should keep hold of some of the 111 returning powers, while UK-wide rules and regulations are drawn up to protect the British single market.
Mr Macintosh said the bill is not within Holyrood’s competence because the EU legislation still applies.
It is the first time the Scottish Government has brought forward a bill the PO has ruled to be outside the parliament’s legislative competence.
His decision, which is not binding, is disputed by the SNP administration and its top lawyer the Lord Advocate, who is due to appear in Holyrood on Wednesday.
A similar bill tabled at the Welsh Assembly had the backing of Mr Macintosh’s opposite number in Cardiff.
Supreme Court judges would be the arbiter of whether a parliament acted beyond its competence when passing legislation.
Scottish Conservative constitution spokesman Adam Tomkins said the tabling of the bill is “both unwelcome and unnecessary” when agreement on the withdrawal bill at Westminster is close.
“Up until now there has been a constructive approach from both the UK and Scottish governments,” he said.
“A fix to make this process fit for purpose is within reach.
“But the SNP must now reflect on whether this move will help or hinder the process.”