Rawnsley's tittle-tattle

Politaholic has been reading Andrew Rawnsley's book. This caught my eye (page 364):

"The two men (Blair and Brown) were forced into each others company in the first week of April when they shared a car journey...As they sat in the back of the limo, Blair attempted to engage Brown in conversation. Brown responded by taking out some papers and burying himself in them. He refused to reply to every overture until Blair eventually gave up trying to make conversation. The journey passed in bitter silence".

The source for this is: "Interview, Cabinet Minister".

Well, how did the unnamed Cabinet Minister know this? There are several possibilities:

1. He also was in the car (Rawnsley doesn't make it clear if Brown and Blair were, apart from the driver, alone)

2. He was told this by either Brown or Blair; presumably, since the story reflects badly on Brown, by Blair.

3. He was told by someone who in turn had been told by Blair.

We don't know whether the source is relaying first, second, or third hand information.

Two questions arise. First, since the story is anti-Brown and the only source is presumably a single Blairite Minister who may not have witnessed the event in question how much credence can be put on it? I mean, how much weight does evidence from, to take hypothetical examples, John Reid or Charles Clarke or Alan Milburn have vis-a-vis an event like this given there is no other corroboration (Rawnsley refers to a "Cabinet Minister" in the singular) and given their well-known dislike of Brown? Second, why the need for anonymity? I suppose it could be the source is someone still in government. Or maybe the source is Blair himself.

I know it is a very small incident. But given the clear anti-Brown bias of this book, it is telling. Frankly I would be reluctant to believe anything an ultra-Blairite says about Brown.