Had John Humphrys asked about his decision to pre-announce his retirement, he would simply not have answered. But for once in his life Blair dropped his guard and gave a totally honest answer, perhaps subconsciously thinking that no one back home would notice.
It was a massive PR mistake. I had gone to bed on Sunday night having watched the BBC political editor explaining how good it was for Blair to be seen with gold-medal-winning athletes, putting all his problems at home behind him. I woke up to hear the same journalist, Nick Robinson, leading on the item about the quit rumours.
It was the use of the word 'mistake' that let the genie out of the bottle, which only compounded the fact that spin doctors had told hacks on the plane out that the PM had privately decided an exit date. Now there is only one question. What's the date, Tony?
Personally I don't think it was a mistake for Blair to say, in September 2004, that he was not going to fight a fourth election. It was a necessary short-term fix and you have to imagine the media frenzy if he had said nothing, or done a Thatcher and said he was to go 'on and on'.
Remember he made his announcement just when two other major stories were about to break. One that he was to have another heart operation, and the other that he had taken out a £4m mortgage on a new house.
Indeed, the fact that Blair went on to win the 2005 election proves he was largely right. The increase in speculation now is mainly due to the wave of 'sleaze' stories and his failure to win over the party on education reform. And even with all that, the last ICM poll still had Labour three points ahead of the Tories.
The PM will only be pushed out if Brown moves against him, which is unlikely unless Blair loses the support of the majority of his MPs, as happened to Charles Kennedy.
He's going to have a rough ride though. There are dozens of angry British hacks who spent 19 hours on a plane, at huge expense, only to listen to Aussie radio report what the PM would never tell them.