By Nick Assinder BBC News Online political correspondent

Blair is not about to hand over his job

What he said was that the chancellor's ambition to be prime minister was "not an ignoble one".

What he meant of course was: "Over my dead body."

Or, in his own words, this is a partnership based on the simple fact that: "I am the prime minister and he is the chancellor."

Got that Gordon, Tony Blair is the boss.

And once again he is making it abundantly clear that he has no intention of standing down and handing you the keys to No 10.

Subtly different

Meanwhile, the two men are engaged in one of their now ritualised displays of unity.

These involve the prime minister saying one thing - this time on tuition fees - and the chancellor offering his full support while saying something subtly different.

By far the most important development is that it appears the prime minister really is ready to go to war over this one.

In this case, Mr Brown has backed the prime minister's determination to reform university funding, but carefully avoided supporting variable fees, the bit Labour's backbench rebels feel most strongly about.

So what is new about all this? After all, it has long been accepted that the New Labour government has to been viewed through the prism of the Blair-Brown relationship.

Probably two things have changed.

Stop it

First it is thought the plotting by the Brownies - who believe they can detect the odour of decay from the prime minister - has gone beyond the point where it can be killed off.

Even if the chancellor told his principle cheerleaders to stop it they would almost certainly dismiss the suggestion, believing "he has to say that doesn't he".

And there has already been a touch of that in response to Mr Brown's suggestion he has urged his supporters not to oppose top up fees.

But by far the most important development is that it appears the prime minister really is ready to go to war over this one.

If his internal detractors want to make this the life-or-death issue for his premiership, then he appears up for it.

On the line

There are those in Westminster who believe the prime minister has "had enough".

He has had enough of the plotting by the Brownies, he has had enough of the carping from his MPs and he has had enough of having to fight tooth and nail to get every piece of his reform package through the Commons.

Brown may tell his supporters to cool it

So, the argument goes, he is ready to see this policy as the one on which he stands or falls.

He really means it when he says his authority is on the line over this policy.

"Rubbish", howl his detractors. They believe this is all part of a strategy aimed, not at risking his leadership, but carefully strengthening it.

Many believe the prime minister is ready to offer significant concessions over this policy - as he has done over previous ones such as foundation hospitals - which will buy off enough rebels while still allowing him to claim victory.

No law

It is a risky strategy. If he fails to pull it off and is defeated in the Commons his leadership bluff - if that is what it is - will have been called.

Only then will we really see whether he meant it when he suggested his leadership may be on the line.

That, of course, is precisely what many of the Brownies are banking on. But they are only a part of the fees rebellion.

For the rest of the rebels, they have to calculate whether they really want to call the prime minister's bluff and enter the next general election with a different leader.

And there is still no law that says that alternative leader has to be Gordon Brown.