This article in the Guardian is the last nail in the Iran War coffin. The UK's Attorney General has a legal opinion that use of UK bases for a pre-emptive attack on Iran could be illegal.
The war that I've always said wouldn't happen is now dead. The US Air Force cannot carry out an extended campaign against Iran without UK bases. They need UK bases for B52s and Diego Garcia for B2s. Of course the US could still use their bases in the US and Guam, but that radically reduces the tonnage they can drop. And use of those bases makes for some difficult overflight problems. The US Navy can still attack from aircraft carriers and the Air Force can use regional bases, but they can't stop the Iranians with conventional weapons. Without strategic bombing, the only way for the US to destroy the Iranian program is with nuclear weapons. And that's not on.
You can stick a fork in it now. We will still hear lots about it, because the general public does not grasp the operational constraints. But it will be just talk. This game is over.
I should have said that this kind of finding means, in my opinion, that Britain will not go to war over the idea of Iranian nuclear weapons. This is a policy document pretending to be a legal document. It moves Britain closer to the overall European position.