A few weeks ago we reported very real concerns about the choreography in the aftermath of the summit from Eurosceptic cabinet ministers, worried that the PM would be setting the pace and terms of the debate in its vital early hours.
While they didn't commit officially to a position, the sense in Downing Street was that there was no need to shift cabinet from its usual Tuesday spot.
They hoped and expected that cabinet ministers who wanted to campaign for exit would keep their counsel until then, when the government had adopted its official position.
But in truth, at least one senior figure had already resolved to break their silence and reveal their plan to campaign for Out over the weekend, in defiance of Number 10.
With that knowledge, and several frank conversations with Eurosceptic ministers, David Cameron's team have decided to relent. This is not just a story for political process nerds (honest), but it illustrates how Eurosceptics, although in a clear minority in the cabinet, have been able to force Downing Street's hand.
This week's summit and now, the 24 hours that follow, are shaping up to be some of the most important in David Cameron's political career.

National Lottery operator Camelot said that, subject to validation, the prize could be paid out on Monday.
It was the eighth ticket in the UK to take the top Euromillions prize so far this year and the fourth this month.
A £19.7m jackpot was shared by three tickets from the UK on 2 September. Friday's winning numbers were 5, 8, 14, 22, 32, and Lucky Stars 2 and 11.
When jackpots are paid, winners can decide whether to reveal their identities or stay anonymous.
A family syndicate from Monmouthshire won more than £61m in the Euromillions jackpot in August.
UK ticketholders also won jackpots of £24.6m and £24m in February this year, and £51.8m in April.
The biggest lottery prize in UK history is the £161m Euromillions jackpot won by North Ayrshire couple Chris and Colin Weir in 2011.
Tickets for Euromillions are sold in nine countries - the UK, Austria, Belgium, France, the Irish Republic,  Luxembourg, Portugal, Spain and Switzerland - with ticket-holders in all each country trying to win a share of the same jackpot.

Concerns had been raised over readiness of the two countries to co-host the competition amid threats of fan violence and racism.
But in a BBC Sport interview, Pohorecki said Euro 2012 had been a big success.
"We feel pride because a lot of people didn't really believe we could make it and we did," said Pohorecki.
Host nation: France
How many nations? 24 countries  for the first time, up from 16 in 2012, playing 51 matches over one month
Clashes between rival Russian and and Polish football fans in the Polish capital Warsaw marred a Euro 2012 tie between the two teams on 12 June.
But while admitting lessons had been learned, Pohorecki played down both that incident and also isolated cases of racial abuse from supporters.
"From all the specific reports I have, there is always something you can do a little bit better for the next tournament," added Pohorecki.
"And the next tournament is in France so we will pass our knowledge on to them."
He added he had been "surprised" by the BBC Panorama programme days before the tournament which asked whether Uefa should have chosen Poland and Ukraine to co-host the event after revealing evidence of racist violence at football matches in both countries.
"I was surprised by it [Panorama] because in every country you can make this kind of programme," insisted Pohorecki.
"You can make it in England, you can make it in the Netherlands... this kind of message I think you can make in any country.
"At this kind of event, the size of the event, by definition and statistics there will always bring issues.
"But if you have riots in Warsaw and then after you have a report from the medical side which shows six people in hospital... six people in hospital is a normal day.
"A regular wedding in Poland is usually six people in hospital! So everything is about how you want to show it."
Pohorecki backed Uefa president Michel Platini, who said the 2020 European Championship could be spread across various cities in Europe, rather than having a single host.
"Why not? Is it a crazy idea? We will see," he said.
"Never say anything is impossible because everything is possible."
This afternoon Number 10 has bowed to the inevitable, and conceded that if (and it is still an if) the deal is done at the EU summit in Brussels this week David Cameron will hold a cabinet meeting as soon as he returns to London early on Friday evening.
[NEXT_CONCEPT]
A UK ticketholder who won a £34m jackpot in Friday's Euromillions draw has come forward to claim the prize.
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Euro 2012 executive director Krzystof Pohorecki says Poland and Ukraine have proved the doubters wrong by hosting a successful tournament.