The government's hopes of passing the EU Withdrawal Bill by Easter are being crushed by the weight of amendments from MPs on all sides.
By Tuesday afternoon a total of 387 amendments had been tabled, but more are expected before the week is out taking the total to over 400.
One senior Conservative backbencher, who asked not to be named, told City A.M. there were many "sensible" points being raised, but admitted there were a handful of Tory rebels looking to block the bill, as well as a "minority" among Labour MPs.
"Clearly the volume [of amendments] is as much an attempt to slow down the bill as it is serious attempt to improve it," he added.
Another said while he did not expect the bill to be blocked, it was getting "harder and harder" for the government to get it onto the statute book by Easter. "The government was hoping to get it to the Lords before Christmas. If it doesn't go to committee soon we do have serious problems."
A third said: "It's just impossible to know [if the bill will be passed]. It all depends on the Tory Remainer rebels, of which there are not huge amounts, though they are active."
Conservative MP and arch Remainer Anna Soubry told City AM the bill "must" pass, but declined to rule out voting against it if the amendments she sought, particularly around the "unacceptable" Henry VIII powers, were not made.
"It’s not a question of blocking it… let's not use the word blocking," she said, although added the bill was "bigger than any party".
Soubry, who recently met with the PM to discuss her concerns, acknowledged there were "certain things for the government to concede", but said the constitutional issues must be addressed. Equally a clause enshrining transition would "be hugely symbolic, would help Theresa May hugely in her negotiations... would really strengthen her hand".
"The mistake [government] has made throughout this whole process is to exclude parliament. Parliament should have been there to assist government and give the mandate to government."
The Lib Dems are so confident that the EU Withdrawal Bill may not pass through the Commons without their help that Brexit spokesman Tom Brake has written to David Davis offering an "olive branch".
The party's eight MPs will back the bill as long as the government agrees to three demands, critically including a referendum on the final deal.
“It is clear the Government no longer have a majority on this Bill," Brake said. "To ease the Government’s pain and to provide some direction to their Marie Celeste of a Bill, I will be willing to work constructively with David Davis to improve the Bill."
A Department for Exiting the EU spokesperson said: “We have already had a referendum and the British people voted to leave the EU: we are delivering on that instruction. The Withdrawal Bill is an essential piece of legislation in the national interest. It will ensure that we have a functioning statute book on exit day, it is not about the terms of our exit from the European Union.”