Mark Ruskell labelled the UK Government bill an “act of self-sabotage” as he sounded a warning over the unprecedented power it would give to Tory ministers.
The MSP made the call during a Holyrood debate on The Impact of Brexit on Devolution.
The bill, first introduced by then-prime minister Boris Johnson in May, would remove at least 2400 instruments of retained EU law.
The Greens say this risks the loss of protections for both people and the environment.
There have also been warnings by experts over the number of laws set to be revoked and the timescale in which the Government is set to revoke them.
The Tories want a sunset period on all EU laws in the UK by the end of 2023 – something lawyers have say isn’t enough time and could lead to a lack of scrutiny.
Ruskell said: “None of the disastrous Brexit outcomes have been surprising, but that doesn’t make them any less painful.
“The UK Government was repeatedly warned about the economic implications of leaving the single market and ending free movement but did it anyway.
“It would be an act of enormous self-sabotage if the so-called ‘Brexit Freedoms Bill’ resulted in a bonfire of the very laws that the UK helped to write.
“There are so many protections and rights that we all rely on, which unless saved will fall off the cliff edge next year. From equal pay to nature protection, laws must be saved and retained. The bill should be scrapped and individual laws prioritised for reform.”
Ruskell (above) said that if Westminster “lights the bonfire” on all EU laws it will put huge pressure on every democratic institution, department and parliamentarian across the UK
He continued: “Parliamentary oversight is a cornerstone of our British democracy. Yet we see post-Brexit legislation coming before both parliaments with broad sweeping ministerial powers, even the powers to amend primary legislation itself without parliamentary consent is on the menu.
“We may have lost the machinery of the European Union. But it’s those European values of openness and democracy that are now more important than ever and we should uphold and defend them in this parliament.”
Scottish and Welsh ministers have raised the alarm over the bill, which they say they were not consulted on.
Earlier this year, Deputy First Minister John Swinney warned the plan posed a direct threat to the powers of the Scottish Parliament.
The UK Government has been approached for comment.