By Mark Mardell
BBC Europe editor, Brussels
As the President of the Commission Jose Manuel Barroso said "think about what we'd be saying tonight if there wasn't a deal", Tony Blair and Jack Straw nodded in heartfelt unison.
Blair was ready to stump up British cash to get a deal
Mr Blair provided his own answer: "We would have been in very serious crisis" and "it would have done immense damage to the British national interest."
Interestingly Mr Blair has paid with hard British cash for the policy of an expanding European Union.
This a deal that nobody adores, but all have grudgingly accepted - that is what successful deals in the European Union are like, almost by definition.
Mr Blair thinks that he'll get away with it at home. The Eurosceptic press have already written the first rebate offer up as "betrayal" a few weeks ago.
Downing Street knows the papers would recycle their copy even if no more was given away, so they might as well slip a few more billions out under the cover of the inevitability of this wrath.
Just as important, David Cameron won't want to make Europe a huge issue within weeks of becoming leader of the Conservative opposition.
Next year it might be a different matter.
So European Union leaders go off to their Christmas break in a much better mood than they left for their summer holidays.
In June the French and the Germans turned on Tony Blair, accusing him of bad behaviour and causing a crisis in the EU because he rejected a deal then.
To cause a second crisis in a year of shocks would have meant Tony Blair would have been cast as a demon in Europe's mythology.
Now instead he's succeeded and enhanced Britain's reputation for being almost wickedly clever, devious and underhand.
He risked alienating his natural allies in eastern Europe by forcing them to take the burden of the cuts and seriously bruised Poland in particular. It'll take a while to mend those fences.
Britain's negotiating tactic was to delay and delay so the first acceptable offer wasn't on the table until the summit was about to end.
That meant seriously annoying people with the first two offers.
One British diplomat likes to describe the cuts to the East as like mugging someone, giving them a nice cup of tea, and then driving them home.
In fact it was cleverer than that - more like mugging someone and then offering them first a fiver and then a tenner back out of their own wallet.
This summit was the international debut of the new German leader, Angela Merkel, and she's earned herself a great deal of credit.
Although President Jacques Chirac tried to pretend otherwise, this wasn't a German-French proposal forced on Britain. It was Mrs Merkel playing honest broker when the presidency was hardly neutral.
She has promised to replace Gerhard Schroeder's chumminess with Mr Chirac (which aides call "macho backslapping") with wider alliances and this was an impressive start.
But what of Tony Blair's grand mission to change the whole direction of the European Union?
He wanted to reinvent its very purpose - to wrench its spending away from farming and give it a modern dynamic economy with a budget to match. This was always a ridiculously overambitious aim.
There will be a review in 2008 about EU spending but there is no mention about when it should kick in.
Mr Blair had been determined that it should be able to affect this budget, the French that it shouldn't.
So the compromise is that there is no mention of timing. This may not be much but it's not exactly worthless.
He has ensured that in two years time there will be a raging debate about farming subsidies and how Europe spends its money.
There is only the possibility of change but the sure-fire certainty of a big bust-up.
Mr Blair said repeatedly that the next time round there had to be "a more rational" budget.
But in some ways the UK has crafted this budget into an even more irrational affair than it would have otherwise have been.
Of course, agreeing a deal with 25 will never be easy but all the sweeteners and special treatments here and there mean it is anything but streamlined.