David Davis has told Conservative MPs the UK’s whole approach to negotiations with the EU risks being undermined by amendments to its flagship Brexit bill.
The Commons will vote later on whether to give MPs a decisive say on any final deal struck with the EU in the autumn.
In a letter to Tory MPs, the Brexit secretary said it was simply not right that Parliament could overturn the referendum result with such a vote.
Theresa May has also appealed to her MPs not to undermine her position.
MPs will be asked to approve or reject a series of amendments made to the EU withdrawal bill by the House of Lords.
BBC political editor Laura Kuenssberg said the numbers are still rather dicey for the meaningful vote amendment, with the prime minister warning that any defeats on this key piece of legislation would send the wrong message to Brussels.
Ministers – including Mr Davis – earlier backed a compromise on future customs procedures.
The government has agreed to report to Parliament by October on efforts to negotiate a customs arrangement with the EU after Brexit.
The fallback position has won the backing of a cross-section of leading Tory MPs on either side of the Brexit argument, avoiding for now a showdown over calls – backed by the House of Lords earlier this year – for the UK to remain in a fully-fledged customs union with the EU after it leaves.
But the BBC’s political editor said the prime minister was still under pressure over the terms of the meaningful vote that Parliament will have on any deal she brings back.
There will be two days of votes on the EU withdrawal bill – the key legislation the government needs to pass to make its Brexit strategy work – starting on Tuesday.
The House of Lords has put forward 15 specific changes to the bill which would require a different approach in some key areas.
This week the government wants to kill off most of these changes – but numbers in the House of Commons are finely balanced, with the Conservatives not having a majority and needing the help of Northern Ireland’s Democratic Unionist Party to get their way.
The government opposes the following Lords amendments
The government has proposed its own version of these ones
The government has accepted this amendment
The government is backing a compromise backbench amendment on this
At a specially convened meeting at Westminster, Mrs May told her MPs they must think about the message Parliament will send to the European Union this week.
I am confident I can get a deal that allows us to strike our own trade deals while having a border with the EU which is as frictionless as possible, she said.
But if the Lords amendments are allowed to stand, that negotiating position will be undermined.
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Some pro-EU Tories were reported to be backing away from voting against the government, over fears that a defeat could prompt a leadership contest and see Mrs May replaced by a far more hard-line Brexiteer.
Former Education Secretary Nicky Morgan is reported to have said the customs compromise will buy time for the government ahead of a crucial summit of EU leaders later this month.
I’m told 6 Tory MPs still holding out on meaningful vote and could vote against Govt tmrw Ken Clarke, Dominic Grieve, Anna Soubry, Heidi Allen, Antoinette Sandbach, Sarah Wollaston. Would leave result extremely close.
End of Twitter post by @tnewtondunn
Former Attorney General Dominic Grieve told the BBC’s Newsnight the customs issue had been resolved but he could still vote against the government on the terms of the meaningful vote which he said remained an issue of difficulty.
Rebels have dismissed a commitment by ministers to make a statement within 28 days should MPs vote down the package negotiated by Mrs May, with several urging Parliament to take control in such a scenario.
Labour, which is backing 14 out of the 15 amendments, are urging Tory rebels to seize the chance to decisively shape the course of the negotiations.
There is still a chance of a squeaky moment for the government, or having to rely on votes from some Labour MPs, on a move to give Parliament more power if MPs vote to reject the final Brexit deal.
Sources tell me the numbers are still rather dicey for that so called ‘meaningful vote’ amendment that will take place tomorrow.
There are discussions ongoing among potential rebels about whether they should deploy their forces.
Some of them believe, as they do on the customs issue, that they have the numbers to beat the government if they decide it’s the right moment. Appeals for party unity in the last couple of days, and the compromise on customs seem to have had some sway.
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It is the legislation aimed at ensuring the UK has a smooth transition out of the EU.
It will repeal the European Communities Act, which took Britain into what was then the European Economic Community, meaning EU law is no longer supreme in the UK.
And to avoid a sudden cliff edge on Brexit day, 29 March 2019, it would also convert existing EU law into UK law so the government and Parliament can decide at a later date which bits they want to keep or change.
News Source BBCNews