My opinion: The "leak" of this "secret" UK document is an effort to reverse the jihadist retreat into Europe.
Since President Bush gave a nationally televised speech on June 23rd firmly reasserting our commitment to Iraq, violence in that country has been way down. Both U.S. and Iraqi casualty rates are less than 25% of what they were prior to June 23.
The terrorists in Iraq know that they have lost and that we are not going to back down. So they have retreated to Europe and have shifted their violence beginning with the London bombings. They are trying to undermine our coalition in Iraq.
Someone in the U.K. is not happy about this. So, with a leaked document that contains a speculative contingency about one scenario that is not going to happen, they have created the false impression that we are possibly going to leave Iraq. This is the terrorist's dream, to get us out of Iraq before the democratic Iraqi government has developed its own working security infrastructure.
The objective of the leak seems to be keeping the jihadists focused on Iraq and therefore not going forward with any further attacks in Europe. Like I said, it's my opinion.
There is no physical connection between Iraq and the London bombings. No Iraqi nationals with Iraqi passports are even being reported as having been detained. Leftist however will have no problems believing that this mythical connection actually exists. Yet historically they denied a connection between the 911 US attacks and Iraq.
The facts seem to point to a connection in the style of attack and the Spain bombings. In both cases these terrorists were not completely suicidal. Some of them apparently did not want their virgins. These could lead one to mythically concieve that terrorists (historically referred to as barbarians) located closer to the anarchist side of the Unholy Alliance were responsable.
There is however the possibility that we are winning the war on terrorism and our enemy can no longer afford to sacrifice what few soilders it can muster.