Blair - yes, Iraq was a terrible mistake but otherwise he remains streets ahead of the vast majority of politicians.
Cameron the worst.
This.
(his mistake was managing the Iraq process not starting it IMO)
(Also, TB managed to fend off a vicious and sustained attack for many years without getting as pissy as I would have under the circs, until he was worn down by its relentlessness; thanks Gordon - good NCO but not officer material )