I have never believed in the Blair/Brown soap opera. It's too convenient. I am sure that Blair and Brown agreed on a handover, but I think their plan was to run with Blair until, as inevitably happens in politics, his popularity fades.
Voter fatigue sets in after a decade, and suddenly a PM who can do no wrong, can do no right. At that point, historically, his party "gets it" too. I suspect that the "Granita Plan" was to run a fake conflict between the two throughout Blair's stint as PM and then for Brown to "defeat" Blair and take over. That way, the ZaNU Labour reign can continue when Blair is a spent force. In the meantime, a few "leaks" from the "supporters" of the supposed rivals and the soap opera has the ability to put the real Opposition out of the headlines at will.
The perception that the Tories won another election by dumping Margaret Thatcher for the pathetic John Major probably inspired the plan.
By providing its own opposition, New Labour has kept the hopes of the Old Labour voters alive. Brown is no more an authentic Old Labourite than Blair (although with his crabbed and miserable looks he seems more like it). He will get a new "honeymoon" period from the Labour Party when Blair goes. If the handover is judiciously timed, the honeymoon will include an election and an historic fourth term.
I am not sure Britain's economy can survive that; still less what remains of our liberties.
No rift with Brown, says Blair | the Daily Mail