Legislation paving the way for Theresa May to start the Brexit process will be published on Thursday.
The first salvo in the parliamentary battle will be fired as ministers produce a Bill which will allow the UK to trigger Article 50, the formal procedure for leaving the European Union.
The government was forced to draw up the legislation after losing an appeal at the Supreme Court, where judges ruled that parliament must give permission to start the Brexit process.
The Bill will be rushed through both Houses of Parliament within weeks in order to meet the prime minister’s deadline for triggering Article 50 by the end of March.
Government confident
The timetable has yet to be set out for the debates and votes in the Commons and Lords, but Downing Street says parliamentary time is available as early as next week.
The legislation will face attempts to amend it from all sides, while some MPs and peers will just oppose it outright – although the Government is confident that it can get the legislation through Parliament.
Members in both Houses will be acutely aware that appearing to frustrate the progress of the Bill would risk accusations that they are going against the will of the people expressed in last year’s referendum.
But the Liberal Democrats have vowed to oppose Article 50 unless there is a guarantee of a fresh public vote on the final Brexit deal agreed with Brussels, and the SNP has vowed to table 50 amendments to the legislation.
There will also be pressure on ministers to produce the promised White Paper on Brexit – announced by Ms May at Prime Minister’s Questions – before the crucial votes on triggering Article 50.
Within the Labour ranks, pro-EU MPs have indicated they will vote against the legislation even though leader Jeremy Corbyn has insisted his party will not block Article 50.
Likely to table amendments
Would-be rebels look set to avoid disciplinary action, with senior Labour sources indicating that Mr Corbyn recognised the “difficulties” they face from remain-supporting constituents.
Shadow education minister Tulip Siddiq said she is ready to step down from her position if necessary in order to represent the views of her north London constituents, who voted overwhelmingly to remain.
But a senior Labour source said no decision had yet been taken on whether to impose a three-line whip on MPs, which would normally require frontbenchers to resign if they wanted to vote against the Bill.
Asked whether frontbenchers who vote against Article 50 would have to resign, the source said: “Obviously, there are difficulties for particular MPs and that is understood.
“But we will be expecting MPs and asking MPs to ensure that Article 50 is triggered.”
Labour is likely to table amendments to the Article 50 Bill on protecting workers’ rights and the environment, as well as ensuring the Government is subjected to scrutiny during negotiations.
And it is expected to try to amend the Bill to require a “meaningful” vote at the end of the process.
This would enable MPs to send ministers back to Brussels to seek a renegotiation if they do not approve of the deal which has been struck.
– PA
