Let me start this out by saying that I have nothing but sympathy for the British Sailors in Iran and their Families. They should, most certainly, be released. I do not know whether they were in Iranian waters or not, but they certainly do not seem to have intended to be in Iranian waters.
With that said given all of the Tension between Iran and 'the West' recently
it is certainly understandable if the Irianians are a bit paranoid these days. Also, if Blair says that these sailors were not supposed to be in Iran, I believe him, but if he says that there have been no Coalition missions inside Iran, even for reconnoissance, that I would find doubtful.
Given all of this, you would think that US and UK forces who do not intend to be inside Iran would take extra precautions to stay well clear of it. This is especially true because, since 9/11 the US and it's allies have operated well outside the Geneva Convention and the rule of International Law.
The secret history of America’s “extraordinary rendition” program.
Despite all of this the Iranians seem, by all accounts, to be treating the prisoners reasonably well. At the very least they do not appear to have been injured or tortured.
Whether or not anyone wants to say the word, Iran and the US (and by association Britain) are in a state of war. This though is the particularly fragile part of that state of war where the shooting hasn't actually begun. Everyone, I think, needs to pull back from the brink a bit and take a deep breath. If this is going to be resolved by negotiation rather than weapons, the rhetoric needs to climb down a notch.
Should Iran have nuclear weapons? Of course not. No one should. Perhaps they should start negotiating around that idea.