1) The brits screwed the whole region up ... and have a lousy reputation. People in the region still blame the Brits for all their ills. For better or worse, its a simple fact. Anyone with any "arab street" knowledge knows this. The brits, quite simply, are not trusted. How can they be honest brokers if they are not trusted? (One significant example is the creation of the State of Israel by Britain, but there are many more such as Iraq's straight line boundaries established by the Brits, Puppet [non-democratic] governments around the Persian Gulf established by the Brits, ...)
2) The brits have systematically leveraged US assets and power. They have basically manipulated the US to take the lead in the region ... and in effect contaminated US reputation with their own. In every case, their idea is basically to get the United States to spend the blood and treasure to further British interests. Any reccomendation by the Brits will only serve their own interests. (One good example (and there are many): Look at Iraq, they put up 10,000 troops versus over 100,000 by the US...and they are claiming half the oil ...almost all of the oil in the south, or look at Iran in 1952 [the toppling of Mossadegh] or look at BP's oil grab in the Caspian, etc. etc.).
3) There will be lies, lies and more lies from the Brits. It will not even be half truths, or colored statements. The Brits will outright lie to serve their own interests. Look at the false intelligence they fed the US about weapons of mass destruction. When their chief weapons investigator (Dr. Kelly) spilled the beans about Blair's lies, he was summarily killed... It is sad, but true that Americans are seduced by a British Accent... and have a hard time separating british statements from reality ...especially when it comes out of a Brit's mouth.
4) The Brits have just polarized the Islamic world again...against them with awarding Rushdie (author of the Satanic Verses with negative suggestions about the Quran) an OBE (one of the highest national awards). This award was made from Blair's office. How can they be repected brokers while irking the islamic world. (Its just plain stupid and may have damaged Britain's future role in the region permanently. Its one thing to protect free speech, and protecting an author (that was correct and good), Its totally another to award him a national medal of honor for what he wrote.)
5) Blair actually has a somewhat positive record as a Prime Minister. And, everyone knows that the Israeli/Palestine situation can not be resolved today. Not now..maybe later..but not now. The Israeli's are simply not motivated to make a fair deal. It will be a failed mission. Anything he does will also exacerbate media attention on the failures in Iraq. He needs to run away from the Middle East not get more engaged in it. He would be better off getting involved in Africa - where (a) he helped transform their debt obligations and help revitalize the continent, and (b) where the Chinese are systematically gaining influence, and (c) where there are real (near term) opportunities for improvements and positive impact.
The more I watch Condi, and interpret her recommendations, the more convinced I am that Condi is the key to Bush's dumb moves. Reccomending Blair for this role is just plain dumb.