Theresa May will seek to overturn all 15 Lords defeats on her flagship Brexit legislation in a single dramatic day next week, putting her authority on the line.
MPs have been warned they will be voting into the early hours of Wednesday morning when the EU withdrawal bill finally returns to the Commons next Tuesday, after weeks of delay.
Key controversies including leaving the EU customs union and single market, the Irish border and parliament’s power if the government’s exit deal is rejected will all be up for grabs.
However, the decision to try to ram through 15 votes in a single sitting – on all the crucial Brexit issues – immediately drew fierce criticism from Labour.
Chuka Umunna, a leading opponent of Brexit, tweeted: “Tabling only 12 hours of debate and votes for 15 amendments shows this government is running scared of the Commons defeating them on the EEA and Customs Union.
And David Lammy, another pro-EU Labour MP, said: “This shows total contempt of parliament to try and railroad 15 amendments through in just a single session.
“This piece of legislation will have huge consequences for the future of our country for generations to come.”
Three days of debate were expected on the Lords amendments, not a single 12-hour sitting – with an entire day for the customs union and single market.
The legislation was ripped apart during its 20-day passage through the Lords, where the 15 defeats also included reversals on the feared loss of environmental and human rights protections.
Tory rebels are confident they can repeat some of those defeats in the Commons – which had prompted a fearful Downing Street to put the bill on hold.
There was even speculation that it could be abandoned altogether and subsumed into the legislation to implement the Brexit deal – which must pass by next March.
However, the prime minister was under fierce pressure from Brexit-backing Tories to face down her pro-EU rebels and enforce her promises on the customs union and single market.
In a letter to Conservative MPs, chief whip Julian Smith warned them they would be voting “well beyond” the normal finishing time, on “a number of divisions”.
And he made a pointed reference to voting in line with “both the referendum result and the Conservative party manifesto we all stood on last year”.
The biggest flashpoint is likely to be over the customs union, after the cabinet’s failure to agree a common position on future customs rules to take into the negotiations.
The successful Lords amendment did not state the UK should stay in a customs union, only requiring the government to set out, by October 31, the steps it has taken to negotiate one.
However, defeat in the Commons would increase the chances of a later vote, on the trade or customs bills, in favour of membership.
The showdown on the EEA [European Economic Area] – in effect, staying in the single market – will see a huge Labour revolt against Jeremy Corbyn’s rejection of the proposal.
The “meaningful vote” amendment passed by peers would require the prime minister to “follow any direction” set by MPs if her deal is rejected – potentially delaying Brexit beyond next March.