I am quite willing to accept that the 'leaked memo' setting out what Blair apparently really thinks about Brown was not penned by Blair himself. But it was certainly penned by someone close to the man, and there seems little reason to doubt that it accurately reflects his feelings towards his successor.
Whether Blair authorised the 'leak' is at best uncertain; but there seems little room to doubt that it was 'leaked' by someone close to the man himself.
Those questions, however, are pretty irrelevant. The point is that it has been deliberately placed into the public arena, and Brown and the Labour Party are left to deal with the consequences.
The first consequence is that it utterly destroyed any attempt to present the party, or even the cabinet, as being united behind Brown. They clearly are not; and even the attempt by No 10 to insist that they all said that they were backfired as some cabinet members very pointedly managed not to do so.
The second consequence is that it effectively confirms that many in the Labour Party have given up all hope of winning the next election. If they believed that the situation was recoverable, they'd be holding this discussion internally, not publicly. They have reached the point where some of them are convinced that the best that they can achieve is damage limitation. In essence - will the Tories' majority be less if we drop Brown now than it will if he hangs on to the end? Or put another way; can we still win the next-but-one election?
Of course, Blair and his allies blame Brown. But if Blair had kept his Granita promise rather then duplicitously leaving Brown to brood for so long, might it all have turned out very differently?