When I first saw this, I have to say my first reaction was that it was a spoof. Someone on another blog has likened it to an Armando Iannucci sketch and I think that's about right.
But Kevin Maguire, loyal Brownite though he may be, is not the kind of reporter who gets spoofed. Whether or not Blair himself ever saw the memo, I do believe it is genuine.
What it shows, above all, is that whatever tenuous grip on reality might once have existed within the Blair Bunker has now been completely and irretrievably lost.
The memo states that Mr Blair "needs to go with the crowds wanting more. He should be the star who won't even play that last encore. In moving towards the end he must focus on the future."
It's that phrase "needs to go with the crowds wanting more" that does it for me. Has whoever wrote that picked up a newspaper lately, or read the opinion polls, or spoken to ordinary voters, or Labour Party members for that matter?
If they had, they would know that the country, and the party too, is fed-up to the back teeth of Blair, has been for some time, and just wants him to get on his bike.
The last conceivable date at which Blair could have "gone with the crowds wanting more" would have been immediately after the overthrow of Saddam Hussein in the Spring of 2003, before it became clear what an evil morass we had involved ourselves in, or how far the public had been deceived into backing the war in the first place.
This evident loss of touch with reality is all of a one with that strange "Anthony" mug with which Mr Blair appeared at his recent monthly press conference.
"You're a man who's in charge, others follow your lead. Your refined inner voice drives your thoughts and deeds. You possess great depth and have a passionate mind. Others think you're influential, ethical and kind," it read.
A few years back, the Downing Street spokesman Tom Kelly sought to rubbish his namesake Dr David Kelly by describing him as a "Walter Mitty Charachter," ignoring, for instance, the pivotal role which Dr Kelly played in verifying the disarmament process in Russia after the fall of the Berlin Wall.
Well, who is Walter Mitty now, Tom?
Of course, Tony Blair has always had a Messiah complex. I don't mean he thinks he is Jesus Christ, but he does think that he is in some way the chosen one, a modern-day Moses perhaps, the only one capable of leading his people from the wilderness to the promised land, perhaps even the only one capable of keeping them there.
What is outlined in the memo is not so much a resignation, as an ascension into heaven, or at least into the bright, sunlit uplands of elder statesmanship.
As Maguire states: "Privately a highly detailed battle plan is in place that aims to catapult Mr Blair out of office and into elder statesmanship with as many bells and whistles as possible. The key aides masterminding the most drawn-out exit in British political history have thought of everything - even a celestial choir, courtesy of Songs of Praise.
"While Mr Blair scolds us for "obsessing" over his exit date, it is clear he is a lot more obsessed."
But to those of us who have spent the better parts of our careers following the fortunes of Tony Blair and New Labour, none of this should come as a great surprise.
Mr Blair was spun into office in the first place, and to be spun out of office courtesy of a carefully co-ordinated series of photo-ops and interviews would doubtless be an appropriate end for the Great Charlatan.
Environment Secretary David Miliband has said today that he reckons it will happen in 12 months time, but whether or not that constitutes confirmation of the wretched "timetable" which Mr Blair was only days ago seeking to deny us, he won't last that long.
All political careers end in failure - but Blair's is now in danger of ending in farce.
Blair-must-go watch update:
Chris Bryant, Sion Smon and 15 other Labour MPs
The Daily Telegraph
The New Statesman
BBC Newsnight poll
Times Populus poll
Wayne David, Don Touhig and other Welsh MPs
Footnote: Mike White of the Guardian, who was widely believed to have counselled his newspaper against calling for Blair to go this year, is now calling for "a dignified exit" soon.