Government documents which suggest Boris Johnson agreed to suspend Parliament two weeks before making it public have been released to the media.
The memos emerged earlier this week during a failed legal challenge to the prime minister's plan.
The Court of Session has now agreed to a request by the BBC, the Times and the Sun to release the documents.
They include a note sent to the PM on 15 August asking if he wanted to prorogue parliament from mid-September.
A handwritten tick and the word "yes" can be seen on the document.
The documents also include a note, apparently handwritten by the prime minister on 16 August, which described the September session of Parliament as a "rigmarole introduced to show the public that MPs were earning their crust" and that he saw nothing "especially shocking" about this prorogation.
A third document contains minutes of a conference call between the prime minister and his Cabinet on 28 August - the day that Mr Johnson publicly announced that he wants to shut down Parliament for five weeks from next week, ahead of a Queen's Speech on 14 October.
It records Mr Johnson as stressing that the decision to prorogue Parliament was "not driven by Brexit considerations" but was about "pursuing an exciting and dynamic legislative programme to take forward the government's agenda".
But it was acknowledged during the discussions that Parliament would not normally be suspended for more than two weeks. The minutes predict that: "The government would be attacked for this decision, but it would be manageable".
The minutes also set out the "messaging" that ministers were to use to combat criticism of the move and records that Mr Johnson warned there was "a high chance" that he would fail to get a new Brexit deal with the EU.
And they quote an unnamed government minister as warning that the move could "impact on the sittings days available to pass the Northern Ireland Budget Bill and potentially put at risk the ability to pass the necessary legislation relating to decision-making powers in a no-deal scenario.
"This would be a significant decision for the future of Northern Ireland".
The documents were released by a panel of three judges at the Inner House of the Court of Session in Edinburgh on Thursday. Some sections have been redacted, despite a request from the parliamentarians that they be published in full.
The judges have been hearing an appeal by a group of MPs and peers who want them to overturn a decision delivered by Lord Doherty at the court earlier this week. They are expected to announce their decision on Friday.
Lord Doherty ruled that Mr Johnson had not broken the law, and said it was for MPs and the electorate to judge the prime minister's actions rather than the courts.
The government sent the memos to the legal team acting for the parliamentarians at 22:55 on Monday evening - just hours before the court hearing before Lord Doherty started the following morning.
During Tuesday's hearing, the parliamentarian's lawyer Aidan O'Neill QC told the judge that one of the documents was a note sent by the government's director of legislative affairs, Nikki Da Costa, to the prime minister and his special advisor Dominic Cummings on 15 August.
Mr O'Neill said the note was headed "ending the session", and asked: "Are you content for your PPS (principal private secretary) to approach the palace with the request for prorogation to begin with the period 9 September to Thursday 12 September and for the Queen's Speech on 14 October?"
Beside that paragraph was a handwritten tick and the word "yes".
The QC said: "One presumes this is a document which was sent in the red box to the prime minister for him to read at his leisure in the evening of 15 August in which he says 'yes' to approaching the palace with a request for prorogation.
"That appears to be developing government policy as of 15 August, but this court was told nothing of that (by UK government lawyers) and was told in fact that this judicial review is academic, hypothetical and premature.
"That is not true. This court and these petitioners were being actively misled."
The group of more than 70 largely pro-Remain politicians, headed by SNP MP Joanna Cherry, argue that Mr Johnson is exceeding his powers and attempting to undermine democracy by avoiding parliamentary scrutiny before the UK leaves the EU.
A similar challenge to Mr Johnson's plan by anti-Brexit campaigner Gina Miller started at the High Court in London on Thursday.