ARE we now roaring flat out towards a cliff-edge Brexit with Jacob Rees-Mogg's foot firmly on the accelerator? It certainly seems so. The Prime Minister's White Paper, the attempt to remain in the EU regulatory framework without actually being a member while somehow conjuring an Irish border solution, was trashed almost before the ink was dry. Not just by Brexit's usual suspects but, solemnly and almost regretfully, by the Brussels negotiators. The EU has not moved one iota over its four freedoms which underpin the single market, and cannot. There has to be free movement of people and goods. To believe otherwise was idiocy. But we've known that since the morning after the referendum. The months since have been a fruitless attempt by Theresa May to keep her party together, with the predictable consequence, chaos.

Unless there is some unforeseeable u-turn we will be propelled over the edge next March. And the carnage will be colossal. In the coming weeks we will be bombarded with increasingly ominous "technical notices" from the UK Government advising us how to prepare, like stockpiling non-perishable food and cancelling these summer holiday plans because well need visas, air travel will be out and, anyway, even if we manage to cross the Channel, through the lorries parked up for miles, forget mobile phone roaming and discount the value of your pound.

So far the Scottish Government has been not so much sidelined as run over by Westminster. The Supreme Court will rule this week on whether the Scottish parliament has the right to pass a Continuity Bill retaining control over devolved powers repatriated from Brussels, but we already know the Sewel convention is illusory and that Holyrood has no legal right to withhold consent if it disagrees with new trade agreements – agreements we don't have anyway.

There will also be a hard border in Ireland, or the Irish Sea, although the DUP seems as intransigent as the Brexiteers on that.

There is only one brake that can be put on this journey to disaster and that is a second referendum on the final deal with Brussels, although with another arch-Leaver, Dominic Raab leading the negotiations and determined to live down to the standards of his predecessor, don't expect much. Jeremy Corbyn and Labour are almost as culpable in putting the interests of the party before the people. In national emergencies leadership is needed. And this is the most serious one in most of our lifetimes. The time for him to act is now.