The Supreme Leader's dreams of solving the world's economic woes and damage limitation at a general election have come unstuck with Downing Street now talking down the G20 get-together and everyone at loggerheads. Cameron is saying sorry and positioning himself as the prime minister-in-waiting.
The G20 London summit was billed as the crowning glory for beleaguered Brown, pinning his hopes on a triumphant plan to save the world, hoping that with Obama by his side some of the shine would rub off and it would be plain sailing to the election.
But that was before the wheels started to fall off with splits a plenty. Now, with a quick reverse gear, Downing Street is at pains to play down the whole thing.
With expectations crashing around his ears and the costs soaring up to a staggering £50m, it's all turning out to be a very expensive damp squib.
In a crafty piece of positioning, Cameron has waded in coming over all statesman-like, as predicted by the Orange Party earlier, apologising for his past cosying up to Brown and now trying to wrong-foot him in the sorry stakes to gain public credibility.
Backing Brown's economic cloud cuckoo land and buying into the sham that the economy was in good shape wasn't fatal for the Tories but it did teach Cameron some harsh lessons. Being honest with voters is always the best policy in the long-run.
That leaves Brown now isolated with everyone including his ministers running around saying sorry.
Brown has even managed to divide G20 finance ministers meeting ahead of the summit, putting chancellor Darling in a bit of a spot. The chancellor now says there is a "need to be realistic" about what could be achieved.
Time and again Brown staked his political life on the success of the summit. That prompts the question have Darling and Brown fallen out as tensions rise before G20?
G20 was played up and played down depending on the flavour of the month. Now the London summit is being billed as just a "modest and businesslike" affair.
But talking up expectations is exactly what Brown does. It happened with the 'economic recovery plan' last summer, it happened with the Washington audacity of hype tour and it's happening now with G20.
Brown's grand plan for a 'Global New Deal' and love affair with Obama are at the heart of tensions and souring relations, with Brown pushing the Obama line to borrow and spend, while France and Germany want to focus on stricter regulation.
Over the Pond, the White House has made it quite clear the Obama administration was not going to "negotiate some specific economic commitment" in London.
So with no firm US commitments and reports of splits, questions are being asked about the ultimate value of Brown's 'global bargain'.
The gathering of world leaders could land taxpayers with a £50 million bill, though Downing Street reckons the cost will be a snip at £19 million.
External consultants are charging a fortune for work. The cost of designing the logo was £6,000.
Obama is only coming over to have a chat and cup of tea with the Queen on his way to a Nato meeting in Strasbourg.
Back home he's lost virtually all Republican support and a good deal of Independent support, as he presses ahead with a wasteful, earmarking, pork-barrel spending spree and his popularity takes a dive in the opinion polls.
The cost of all this will seem very high to hard-pressed families struggling in the depths of a deep recession depression.
For an isolated and deluded Brown the game is up. G20 was the last roll of the dice and the only way forward for Brown is down. £19 million plus is a lot of taxpayers' cash just to massage his faltering ego.