I've been passed a document headed: "Indicative votes before second reading of the WAB" (Withdrawal Agreement Bill).
It is an official summary of what the government had hoped to agree with Labour by way of a Brexit compromise, and how to test the will of the House of Commons on what kind of customs union or arrangement would be appropriate for the UK.
Strikingly it shows Theresa May and her cabinet trying to achieve two other things: they want to use so-called indicative votes by MPs in just the next few days to prove MPs do not want a confirmatory referendum, and that they do want to leave the EU on 31 July.
If Jeremy Corbyn were to agree to this, he would split the Labour Party. But there are other elements of the proposed cross-party compromise, namely on customs and a proposed "package agreed with Labour", which would tear the Tory Party apart.
The document shows the government wants to hold these indicative votes next week, before the EU parliamentary elections and the short recess.
"We would make an emergency business statement on Monday; votes would take place on Wednesday," the paper says.
It adds: "Whilst neither the Government nor the Opposition can commit to be bound by all of these votes, the purpose of holding them is to test the will of the House and, as far as possible, reflect that in the WAB to maximise the chances of it securing Royal Assent. To that end, the Government and the Opposition will consider not just the result of each vote but the level of support for it".
In other words, the cabinet wants to bind Labour's leadership into a rolling process of assessing what compromises are necessary to secure passage of its Brexit legislation.
If these votes were to take place next week, there would be a dizzying five categories of them, and I reproduce them below.
The section that may confuse you is 3), because this contains four different customs options. The paper says that MPs would be "able to vote for as many [customs] options as they want and the option with the fewest votes [would be] eliminated in each round".
Importantly, this vote on customs would be a free vote. And it will be seen as an attempt to enlist the support of Labour MPs for a customs union or customs arrangements with the EU that a probable majority of Tory MPs loathe and see as a travesty of a "true" Brexit.
As for voting arrangements on the other proposed motions, the paper wants both government and Labour to whip in favour of leaving the EU with a deal, and getting all relevant legislation passed by the time of summer recess so the UK can be out of the EU on 31 July, and on a "package we've agreed with Labour".
However - and this will outrage many Labour MPs - the paper proposes a free vote on a clause that "the deal should not be subject to a second referendum". This will be seen by MPs who want a confirmatory referendum as an attempt to pre-emptively close down this route.
Here are the five different motions proposed for these indicative votes:
1. A Brexit deal
"The UK should leave the European Union with a deal."
2. Before summer recess
"The WAB [or Withdrawal Agreement Bill] should receive Royal Assent by the summer recess in order that the UK leaves the EU on 31st July 2019."
"A customs arrangement that combines the benefits of a customs union - no tariffs, fees, charges or quantitative restrictions - plus no checks on rules of origin when goods move between the UK and the EU with the ability for the UK to determine its own external trade policy and international development policy.
"A comprehensive customs union covering both goods and services, including a UK say in EU trade policy, at least until alternative arrangements that maintain as close to frictionless trade as possible with the EU and no hard border on the island of Ireland have been agreed.
"A customs union covering goods, including a say in relevant EU trade policy, at least until the next election.
"A comprehensive customs union covering both goods and services including a UK say in EU trade policy."
4. No people's vote
"The deal should not be subject to a second referendum."
5. The package agreed with Labour
"Parliament must approve the UK's objectives for the negotiations on our future relationship with the EU and approve the treaty governing that relationship before the Government signs it.
"The UK should seek as close to frictionless trade in goods with the EU as possible, subject to the UK being outside the Single Market and ending free movement, to protect jobs in just-in-time supply chains.
"In order to deliver as close to frictionless trade in goods as possible, the UK should dynamically align with those EU rules for goods and agri-food products that are relevant to checks at the border.
"The UK should seek the fullest possible participation in EU tools and measures that protect citizens' security.
"The UK should seek the fullest possible participation in key EU agencies, including the European Medicines Agency, the European Aviation Safety Agency and the European Chemicals Agency in relation to the economic partnership and Europol and Eurojust in relation to the security partnership.
"Workers' rights in the UK should be no less favourable than rights in the EU.
"The UK's withdrawal from the UK should not affect the level of environmental protection in the UK."
Now what I find intriguing is that the "package we've agreed with Labour" reads very much like a summary of the PM's Chequers proposal for the future relationship with the EU - which prompted the resignations from the Cabinet of the Brexiters David Davis and Boris Johnson - as much as Labour's blueprint for the future relationship with the EU.
There will be plenty of Brexiter Tory MPs who will hate everything in the document, especially the Labour "package", and many Labour MPs who will argue that it's only acceptable if subject to a confirmatory referendum.
But there are Labour MPs like Lisa Nandy and Caroline Flint - and frontbenchers such as Ian Lavery - who have been urging Corbyn to find a Brexit compromise with the government.
For what it's worth I cannot see Labour signing up to the contents of the document. Although Corbyn has been resisting giving an unambiguous commitment to a referendum, he is acutely aware that maybe half his MPs now want one - including his Brexit spokesman, Keir Starmer - and that they will be enraged if he endorses a document whose purpose seems to be to shut down the referendum route.
I asked the government for an official reaction. To date they have failed to provide one.
The Labour MP Alex Sobel said: "Labour can now take a stand: end the cross-party talks immediately and make it clear there is no prospect of Labour ever agreeing to any Brexit deal that is not handed back to the people for the final say."