The Withdrawal Agreement Bill is a serious piece of complicated legislation. Parliament should treat it as such.

The government has only been able to produce the bill at such short notice because most of the Johnson deal agreed with the EU last week is lifted straight from the deal that Theresa May signed off almost a year ago.

But May’s secretive government, and Johnson’s sceptical government, never gave MPs any chance to have a look at how they proposed to turn treaty commitments into UK law. That is what the bill is meant to do—and it is a very hard read.

The first thing the bill does is turn off the provisions in the EU withdrawal act for the duration of the “implementation period.” So back come provisions to enable the UK to keep pace with EU law; back comes the jurisdiction of the European Court of Justice.

The bill also has to take powers to allow ministers to make the financial settlement; put into effect the guarantees for citizens’ rights—and set up the so-called Independent Monitoring Authority, designed to oversee how the UK implements those rights; and make the necessary provisions to implement the Ireland/Northern Ireland protocol.

It makes a lot of references to the new and powerful “joint Committee,” where the UK will end up agreeing much of how to make the new agreement work once we are in the implementation period, but tells us nothing about how it is constituted—beyond that a minister will be the UK co-chair.

And it makes provision for this treaty to have supremacy over UK law—though as a sop to Eurosceptics being forced to “suck it up” there is a meaningless clause about parliamentary sovereignty.

In many areas the detail is missing—and ministers are seeking extensive powers to enable them to fill in the gaps through secondary legislation.

But the bill isn’t just confined to the provisions of the withdrawal agreement itself: it also has a few nods at other parliamentary concerns. It has provisions on workers’ rights—though these do no more than oblige a minister to inform the House if the government is “regressing” from EU standards.

It’s hard to imagine that gives much comfort to those concerned that a gung-ho deregulatory government might try to rip them up.

It gives parliament a role in future trade negotiations, in approving the mandate for those negotiations—something else that Labour MPs were keen to see. But there is a kicker—that mandate needs to be “consistent” with the Political Declaration which envisages a much looser relationship with the EU than Labour wants.

This seems to be a device to give that declaration some status in UK law—which it otherwise would not have.

Finally, a lot of MPs are pointing out that although parliament would have to agree to a request for an extension of the transition, they don’t get a say on the UK leaving without a deal at the end of transition.

Even if there is an anti-no deal majority in the next parliament, they may not be able to rely on John Bercow’s replacement to be so creative with Commons rules to allow them to frustrate a no-deal government.

Those are some of the issues that emerge on a quick skim. There will be more potential areas of concern which would emerge if parliament gets into the detail—only yesterday it was shown that the Brexit secretary Steve Barclay did not understand how the provisions on Northern Ireland would affect west-east trade.

But the government is determined to stop parliament getting into that detail. Alongside the bill it has tabled a motion to rush the bill through the Commons by Thursday night.

That means barely any time for MPs to think about amendments; it means hardly any time for debate as MPs will spend much of that time wandering through division lobbies. No 10 appears to be threatening to pull the bill together if it doesn’t get its way on the timetable—to allow the PM to meet his 31 October deadline.

The PM may not get his way. He should not get his way. Parliament should insist on a proper chance to scrutinise a major piece of legislation—and the EU should be prepared to agree a technical extension to allow that to happen. It is in no one’s interests for a bad piece of under-scrutinised legislation to get on to the statute book.

Withdrawal is for life, not just for Halloween.

By Jill Rutter, senior research fellow at The UK in a Changing Europe. This piece originally appeared in Prospect.