MPs in the UK are preparing to debate the small print of the British government's Brexit legislation for eight days and nights between now and Christmas.
The committee stage of the EU withdrawal bill gets under way, with Labour and rebel Conservative MPs attempting to inflict a series of damaging defeats on Theresa May and Brexit Secretary David Davis.
Only hours before the start of the debates, Mr Davis attempted to buy off a rebellion by pro-Remain Conservatives by promising a further piece of legislation giving MPs a "take it or leave it" vote on the final Brexit deal.
But his concession has failed to win over many MPs, who claim the vote should be held earlier and that it fails to solve the problem of so-called "Henry VIII" powers which give ministers scope to change laws after Brexit.
The committee stage begins with four hours of debate on the precise timing of when the UK leaves the EU, followed by another four hours of debate on calls for a bigger Brexit role for the Scottish and Welsh governments.
Day two of the debate, on Wednesday, will see eight hours of debate on Labour demands for guarantees on workers' rights and environmental protection.
The first real threat of a government defeat is expected next Tuesday, on the eve of this year's UK budget, when MPs debate the "Henry VIII" powers and 'Remainers' are confident of a rebellion by up to 10 Conservatives MPs.
More than 400 amendments and new clauses to the bill have been tabled, prompting the government to delay the committee stage for weeks while ministers tried to find ways to head off Tory rebellions and potential defeats.
Speaking in Birmingham ahead of the committee stage, Labour leader Jeremy Corbyn said: "Today the misnamed EU Withdrawal Bill came back to Parliament. It is in fact an undemocratic government power grab.
"Its return follows weeks of damaging delay. That has only added to the sense of chaotic dithering around the Conservatives' entire approach to Brexit.
"Nearly 17 months since Britain voted to leave the EU, we are still none the wiser as to what our future relationship with our biggest trading partners is going to look like."