After a disastrous General Election in which Theresa May lost her parliamentary majority, anti-Brexit MPs believe they will be able to defeat the crucial law once it is brought to the Commons.
Mrs May has described it as an “essential step” on Britain’s departure from the EU.
But now the Tories have lost their majority and must now rely on Northern Ireland’s Democratic Unionists to prop the Government up, diehard Remainers in Parliament are increasingly certain they can stop the law in its tracks.
Liberal Democrat leader Tim Farron told the Mail on Sunday: “The Great Repeal Bill is facing a long, hard battle and I plan to fight the Tories every step of the way.
“Our rights and protections must not be eroded. I do not trust Theresa May on this and will work with anyone on a cross-party basis to stop her.
“The Government know they don’t have the votes to get this through. My message is stark: you need to go back to the drawing board or face defeat.”
Lord Wood, who advised Ed Miliband during his tenure as Labour leader, wrote: “There is simply no way the staggering scope, complexity and sensitivities of the Great Repeal Bill can be navigated given the election result.
But top Brexiteers have rubbished the claims, and remained adamant any attempt to block the bill would end in failure.
Veteran Eurosceptic Sir Bill Cash said: “Any attempt to frustrate or obstruct the Repeal Bill would be contrary to the will of the people at the referendum, and what people voted for at the General Election.