The Brexit Bill: your day-by-day guide to what happens next

The European Union (Notification of Withdrawal) Bill was published by David Davis, the Brexit Secretary, last Thursday, and given its first reading in the House of Commons. This literally means its title was read out. Today it begins the rest of its journey to becoming law. Here is our guide to the likely timetable.

First of two days of debate, called the second reading. The Bill’s title is read out, literally, a second time, but this time MPs have a debate on it, at the end of which they vote for or against the Bill in principle.

Second reading debates usually take place on a single day, but because this Bill is important David Lidington, the Leader of the House (the Government’s business manager), has scheduled two days of debate, and the first day is scheduled to be extra long, running until midnight on Tuesday.

Second day of second reading debate. At the end of the debate, at 7pm, there will be a vote on a “reasoned amendment”. This is not really an amendment: it is a motion opposing the Bill and giving reasons it should not become law. Caroline Lucas, the Green MP, has tabled a cross-party one, signed by Labour, SNP and Northern Irish SDLP MPs. Heidi Alexander, a Labour MP, has tabled one signed by 18 other Labour MPs. The Speaker has, however, chosen one tabled by the SNP, as it is the largest group opposed to the Bill, but it will be defeated because the Labour leadership’s view is that the Bill must pass.

Then there will be the main vote on the Bill itself, which will be the big decision point for MPs. Corbyn is imposing a three-line whip on his MPs, asking them to vote for the Bill, because the shadow Cabinet has agreed “not to block Article 50”. It is called a three-line whip because the instruction from Nick Brown, the Labour Chief Whip, is underlined three times, meaning MPs must vote as directed or risk being disciplined. That threat is meaningless for backbenchers, but Corbyn has said that an MP cannot vote against and remain a member of the shadow Cabinet. Jo Stevens, the shadow Welsh Secretary, has already quit. It is not clear whether junior frontbenchers will be required to resign, but Tulip Siddiq, a shadow minister not in the shadow Cabinet, resigned last week anyway.

Finally there will be a vote on the timetable for the rest of the Bill. This is called a programme motion. In the past, government business has been held up when the programme motion was defeated, because then the debate runs on for as long as there are enough MPs in attendance to keep it going. That is what Labour did under John Smith, uniting with Tory Eurosceptics to delay ratifying the Maastricht Treaty. But Jeremy Corbyn will instruct his MPs to abstain on this programme motion, so it will pass easily – although the Scottish National Party and Liberal Democrats will probably vote against it.

First of three days’ debate on detailed amendments. Usually this is done by a small committee of MPs, but some important legislation such as this Bill is considered in a “Committee of the Whole House”. Just for fun, it is always chaired by the Deputy Speaker, whose proper title is Chairman of Ways and Means, currently the Labour MP Lindsay Hoyle. Hoyle will decide which amendments comply with the rules – that is, are “in order” – and he will also decide in which order to take them, which matters because there are likely to be too many proposed amendments to get through in the three days.

Amendments have to be “within the scope” of the Bill, which is quite restrictive as the Bill is so short, just 137 words long. They can also be ruled out of order if they are “unintelligible or grossly ungrammatical”; “vague, trifling or just plain silly”; or if “they seek to do something which would nullify the whole purpose of the Bill”, according to the Handbook of House of Commons Procedure.

Labour has already tabled an amendment that would require Parliament’s approval before the Government concludes an EU withdrawal agreement. And Harriet Harman, chair of the Joint Committee on Human Rights, has tabled one that seeks to protect the rights of EU nationals in the UK.

Second day of the Committee stage.

Third day of Committee, and remaining Commons stages of the Bill. If it has been amended, there will now be a Report stage, which refers to the “report” from the committee to the whole House, but as the committee is the whole House it is a bit pointless. Then there is a “third reading” – the Bill’s title is read out a third time – and another vote. Given that the House has already voted on the Bill and any amendments, this should be a formality.

After that, the Bill will go to the House of Lords, probably after the February recess (10-17 February). Traditionally a Lords second reading takes a day, and the committee stage lasts about eight days; though this Bill may be given longer. It cannot be delayed indefinitely, however, as long as both front benches (Conservatives and Labour) support it, which they do.

If the Lords amend the Bill, it would then return to the House of Commons. Amendments are more likely to go through the upper house, as long as peers think they are not designed to obstruct the Bill. If the Commons doesn’t agree to them they will be taken out and the Bill sent back to the Lords, a back-and-forth known as ping-pong. At some point the House of Lords usually lets the Commons have its way.

In any case, the Bill, possibly amended in ways with which May can live, is likely to be finished by 7 March, the date the Government told the Lords yesterday it wanted. Then it will receive the royal assent and become the European Union (Notification of Withdrawal) Act 2017.