Should Tariq Aziz get luxury home in Britain and protection

Anything is possible. IMHO, he should be put into a high security prison for the rest of his life for participating in Iraq's regime. c.i.

Well, all this resembles witnesses protection program of the FBI: its participants are usually felons themselves, but they provide valuable information to the law enforcers.

What he is probably doing is playing "Let's Make a Deal". If his information is important enough, and it leads to critical information and/or the whereabouts of certain individuals, it might very well be worth the cost!

Is it just? Probably not. I think that he belongs in the pokey, for a long long time. Is it pragmatic, if his information will ensure that the Baath party thugs will be permanently out of commission, that WMD are found, and Iraqi ties to Al Queda are confirmed? Absolutely!