Why do you say Blair performed poorly? I think the man showed composure and was pretty reasonable considering his sailors were taken hostage.
It was because of Blair style of working (hard line diplomacy, no negotiation, recruit UN and Europe verbal and moral support, and even refuse to talk to Iran) that 'harden' the heart of the Iranian government (something similar to God hardening the heart of Pharoah during confrontation with Moses
) which resulted in the no early release of one female detainee. This gave the opportunity for the Iranian government to carry out the work of GOOD GUY, giving first class hotel and food to the sailors and marines, and somehow managed to lure them into confession and appearing on TV (I do not think they used any 'force' ), which gave Iran lots of positive publicity. While Blair is still working on showing a stern face, and no negotiation, suddenly this Ahmadinejad surprised the whole world by freeing the 15 as gift to the UK people (not to the government)!
Another conspiracy theory is that actually British could have done like 2004, and end the business quickly, and get the 15 British free. However that was not the intention of the plan, as it was conspired to create the Tongkin event at the Gulf. Unfortunately, the Iranians were too quick, before the British and US realized it (the helicopter was taking a break from providing the backup (the British high tea time), to spot any oncoming Iranian boats, and carry out a shoot out confrontation incident), in addtion with the British boats making mistakes of wondering too near the line or could have crossed the line, the speed boats of Iranian coast guards zoomed in and got their prisoners. Since the Tongkin episode did not materialize, US and UK went for plan 2, let the 15 British suffered, and took a strong stand and refused to negotiate. Put the blame onto Iran, saying they wanted to exchange for the five detained Iranians etc etc. Blair and Bush were using their own citizens as pawns in this conflict. To Blair, the soldiers or military could be used in the battle in this way, and a bit of sacrificing is acceptable (this is even more acceptable than collaterial damage, since soldiers are officially in the war), if the event can churn up the anti-Iranian feeling at home in UK and US. Unfortunately, UK and US citizens are peace loving people, and have seen through the plot of their government, so they give a quiet support and let Iranian run the show. If Iranians were stupid enough to get tough with the UK, which they have the right if these 15 have wondered into their water before boarding and after boarding for smuggling inspection, they would have fallen into a trap. That will given the perfect excuse for UK and US to invade Iran to rescue the 15 British as originally planned to occur on Easter. Nice story eh?